The Monk class is one of the weakest in the game. It has extremely few powerful or useful features, and those that are useful tend to have extremely tight limits on how often they can be used. The only major exceptions, namely their Unarmed Strikes, AC Bonus, Flurry of Blows, Evasion, and their bonus feats, all happen in the first two levels. There is almost no situation in which it is optimal to take more than 2 levels of Monk.
And in those few cases (using Alternate Class Features), you still max out at Monk 6.
Overview of Monk class features
Just so we’re on the same page, here’s what Monk has to offer. Most of it is pretty weak.
Unarmed Strike Damage
The Monk’s unarmed strike damage is their best feature. Unfortunately, it grows extremely slowly, and you cannot (easily) enhance them as you could a normal weapon, so even though it’s the Monk’s best feature, it’s still not a particularly great feature.
The best way to maximize this damage is by increasing your size. Start as a race with Powerful Build, like Goliath (Races of Stone) or Half-giant (Expanded Psionics Handbook), or maybe even go for some real monstrous race or template, like Half-minotaur (Dragon vol. 313) or Feral (Savage Species). For that matter, the anthropomorphic animals in Savage Species might just be overpowered enough to make a Monk worth something. A Warforged with a Battlefist (Eberron Campaign Setting) gets the damage bonus but not the other benefits of Powerful Build.
Take feats that improve your size for the purposes of your damage, like Improved Natural Attack (Unarmed Strike) (if your DM thinks that you cannot take INA with Unarmed Strikes, or houserules so that you cannot, do not even consider the Monk). Get ways of increasing your size further, like Expansion (Expanded Psionics Handbook), or, if you must, Enlarge Person (but note that Enlarge Person’s 1 round casting time makes it absurdly inefficient in combat, and it won’t work on Goliaths or Half-giants). In a high-level game, get a magic item of these things, or Giant’s Size (Complete Arcane) for growing two size categories. Though your odds of remaining competitive in a high-level game are really low.
If you can, get a Necklace of Natural Attacks (Savage Species); if you can’t, it’s even harder to justify Monk. The Necklace of Natural Attacks allows you to give your unarmed strikes actual special abilities. If you cannot get the Necklace of Natural Attacks, the Scorpion Kama (Magic Item Compendium) can have its damage replaced by your Unarmed Strike damage, so that’s decent, though more expensive. Do not ever buy an Amulet of Mighty Fists. That item is ludicrously overpriced, even for a Monk who needs it.
If you can afford it from character creation, the Fanged Ring (Dragon Magic) is must-have. It’s 10,000 gp, but it gives Improved Unarmed Strike and Improved Natural Attack (Unarmed Strike), as well as a free Con-damaging poison. If you cannot afford it to begin with, you probably need to take Improved Natural Attack on your own; the bonus is just too important.
If you run out of size increases, bonuses to your effective Monk level can work too. Unfortunately, they work slowly, thanks to the fact that the Unarmed Strike damage only goes up one die size per four Monk levels. Monk’s Belt and Superior Unarmed Strike (Tome of Battle) both have these sorts of bonuses (but note that RAW, the Monk’s Belt and Superior Unarmed Strike do not stack; most DMs allow them to though). You may also ask your DM if you could get Superior Unarmed Strike as a bonus feat if something would otherwise give you Improved Unarmed Strike (which you already have by virtue of your Unarmed Strike class feature) – the Fanged Ring becomes even better then.
Flurry of Blows
Also known as Flurry of Misses. You’re a medium BAB class, and you’re taking yet more penalties. Might be worth it for an extra attack, if you had a source of bonus damage like a Rogue does. You don’t, though, and you cannot afford the Rogue’s focus on Dexterity.
Monks have a very hard time hitting things. You cannot afford to go all-in on Strength like other characters might, you need a lot of feats so Weapon Finesse hurts to take (and you still can’t go all-in on Dexterity, either), you have poor BAB, etc. Flurry makes that worse.
This class feature would be much better on another class. For example, the Shou Disciple prestige class is full BAB and gains Flurry, for example; that’s at least better anyway. If you want to optimize Flurry of Blows, you really want two things the Monk does not have: full BAB, and bonus damage dice. There aren’t a lot of good options for getting all of those things, however.
Other Monk Weapons
The Monk gains proficiency in some Exotic weapons; this is yet another feature that you get at level 1 and that gives you no reason to stay in the class. They’re almost entirely worthless anyway, but for completion’s sake:
- Kama: can trip, but no reach. Guisarme is vastly superior for a trip-lockdown build.
- Nunchaku: +2 bonus on Disarm; doesn’t even counter-act the +4 bonus for holding a weapon in two-hands. Disarming is a waste of time anyway when Locked Gauntlets are so easy to use and add such a huge bonus.
- Sai: +4 bonus on Disarm; actually does cover the two-hand bonus, but there’s nothing special about these otherwise. Disarming remains a difficult tactic to use.
- Shuriken: the best of the bunch, because it counts as ammunition. Only worthwhile if you’re really abusing that, though, to get vastly-cheaper weapon enhancements. Only justifies one level in Monk anyway, and Ninja (Complete Adventurer) is arguably better since throwers really want bonus damage.
- Siangham: literally a Short Sword with a smaller critical range. The game would be improved if this didn’t exist and the Monks could just use Short Swords.
Unarmored AC
Actually a decent bonus, but unfortunately you’ve got so many ability scores that you need to maximize that you won’t be able to get a very high Wisdom. Plus, really, most of the time, plain armor is better. And if it comes down to it, the Monk’s Belt replicates this feature for a relatively affordable 13,000 gp.
Maximizing this is pretty obvious: pump Wisdom. That’s really hard on a Monk, however, since the Monk really badly needs Strength, Dexterity, and Constitution as well. This is a major, overarching problem with the Monk, for which there is not really any good answer. Even if you were to roll really high scores, keeping them all high becomes prohibitively expensive by mid levels. This feature is far better for a Cleric or Druid than it is for a Monk.
Bonus Feats and Evasion
Decent, but hardly amazing. Fighters and Psychic Warriors get better feats; Rogues get an awful lot more useful class features along with Evasion. Rings of Evasion are pretty pricey for what they do, but it’s a bad sign when your class features are easily replicated by magic items.
Honestly, these are one of the better reasons to be a Monk. With all of the alternate class features and additional Monk feats in supplements, you can get some good stuff. Usually the idea here is to get a bunch of useful feats in two levels, and move on to something else. Only really worthwhile if you need two feats you can get from Monk and Improved Unarmed Strike, though.
Fast Movement
Just pointing out that you cannot use this at the same time as Flurry of Blows. A pretty good example in a nutshell of what’s so wrong with the Monk. Having high movement is usually close to useless to a PC character – usually running out ahead of your party is a very bad choice, and your party won’t be able to keep up. In combat, distances are only seldomly so large that you’d need the boost.
There’s just... not much purpose to this. It just is.
Slow Fall
This is actually insulting. At 20th level, you gain a version of this that is still worse than a 1st-level spell. That Silverbrow Humans can get as a racial feature, along with several other benefits, in exchange for just the human bonus skill point per level.
This is even less useful than Fast Movement. It affects almost nothing, and nothing affects it. You cannot optimize it in any meaningful fashion.
Still Mind, Ki Strike, Purity of Body, Wholeness of Body, Improved Evasion, Diamond Body, Diamond Soul, Timeless Body, Tongue of Sun and Moon, Perfect Self
A series of small and niche bonuses to things. Almost all of these are pretty easily replaced with items.
Being an Outsider could be useful, but you need class levels in things other than Monk, which you cannot have as a Monk 20 (pre-Epic, anyway). The rest... just don’t do very much. You cannot really optimize these either. The ones that are important (defense vs. [Mind-Affecting] is the big one) should be overwritten with outright immunities. The rest can and probably should be ignored.
Stunning Fist, Abundant Step, Quivering Palm, Empty Body
Mediocre to OK effects with ridiculously tight limitations on them. Quivering Palm is a joke at 1/week. Note that it’s a [Death] effect, which tons of things are immune to and those that aren’t usually try pick up immunity to it. Stunning Fist is in the same category; immunity to Stun is very common and very desirable, so you won’t have a lot of valid targets. Abundant Step is as dimension door which means you cannot do anything after using it, and again, you don’t get to use it very much. Empty Body is good but comes way too late and lasts way too little time.
Unfortunately, while there are ways to optimize some of these (ways to get more uses of Stunning Fist, new and better effects on Stunning Fist attacks), I am not aware of any that are good. Abundant Step is much improved by Shadowpounce (Telflammar Shadowlord from Unapproachable East or Crinti Shadow Marauder from Shining South), but there are much better ways to get teleporting for the purposes of those classes. Generally, these effects require too much investment and give too little return. The optimal thing to do, sadly, is to take what you’re getting anyway, and try not to sink too many resources into them.
Monk Fallacies
There are some beliefs about Monks that are pretty common, but are ridiculously false.
Monks make good tanks
They have a low HD, cannot wear armor, have bonuses but not immunities to a lot of things, and pose no threat to the opposition so there is no reason for the enemy to waste time with them.
At the very best, the somewhat-difficult-to-attack-but-totally-ineffectual Monk may get ignored until the end of the combat, at which point either the enemy is dead (no thanks to him) or his party is dead, and now he runs.
Monks can run away. They are pretty good at that...
Monks make good grapplers
They make awful grapplers. Their grapple check is very low, thanks to their BAB, lack of Strength, and lack of native access to size increases. The damage dealt by any grappler that doesn’t have Constrict is really low; the Monk’s is a little less low but still very low. Grappling is about locking a foe down, and the Monk can’t do that well at all.
For grappling, it’s all about size. Which is why Grappling is really for monsters, not humanoids.
Monks make good magekillers
No, they don’t. They have high saves, but spellcasters have ways to ignore saving throws. They don’t have access to a large number of important immunities. They cannot fly, see invisible creatures, affect incorporeal/ethereal creatures, and so on: These are defenses that mages like a lot.
A lot of this comes from the belief that Monks are good grapplers (see above): freedom of movement and/or dimension door says the mage doesn’t care.
Ultimately, the only people with any real chance of taking down a mid-to-high level mage with any competence is to be another mage, either higher level or more clever. Spellcasting in 3.5 is extremely overpowered.
Vow of Poverty is good for Monks
It’s not; it’s awful for Monks. Monks desperately need magic items to shore up all their myriad deficiencies, and Vow of Poverty prevents you from getting them.
Vow of Poverty is good for Anyone
Vow of Poverty literally grants you bonuses that you can buy for less money than you lose. It is mathematically bad for you, and that’s not even considering the two feats you burned (Sacred Vow and Vow of Poverty itself).
There are a few benefits from Vow of Poverty that money can’t buy; some ability score bonuses and some bonus Exalted feats. Unfortunately, there are very few Exalted feats worth taking; Vow of Poverty will get you those, but then you’ll end up taking random stuff that’s not particularly good but you’ve already paid for it so why not.
The only classes that can take Vow of Poverty and not be utterly crippled are things like Druids and to a far lesser extent, Incarnates and Totemists (both from Magic of Incarnum). And they’re still much better off without it. I’ll give a special mention to the Apostle of Peace, one of the most game-breaking prestige classes in the game (both because it is overpowered and because it literally breaks the game’s expectations and prevents others from playing), since it does require Vow of Poverty.
See here for a full description of the prolems of Vow of Poverty.
Alternative options
Ways to be a “monk” without being a “Monk”
Psionics and Tashalatora
Psychic Warriors (Expanded Psionics Handbook) and Ardents (Complete Psionics) make great “monks” straight out of the box. Both are ¾ BAB Wisdom-based classes, like the Monk, but both have Psionic powers to allow them to do things well. They can both take Improved Unarmed Strike if they want to punch things. They both get Expansion which, in combination to the other items/feats that a Monk would take, is going to likely make them better than a Monk at punching things. And much better at Grappling.
And then there is Tashalatora (Secrets of Sarlona). This feat requires Monastic Training (Eberron Campaign Setting), and allows you to stack any one Psionic class with your Monk levels for the purposes of Unarmed Strike damage, Flurry of Blows, Fast Movement, and the AC Bonus (read: everything that was even half-good on the Monk). Monastic Training can be taken as a bonus feat at Monk 1, and Tashalatora can be taken as a bonus feat at Monk 2. Hilariously, neither feat actually requires any Monk levels, which means for two feats your Psychic Warrior or Ardent can literally have the same stuff as a Monk of the same level, without giving up any of their manifesting.
Cleric: Casting spells while punching things.
Clerics can take Improved Unarmed Strike. They can even get a free Weapon Focus in it if they get the War Domain from a god with it as his favored weapon. More importantly, Clerics can make great melee combatant: buff up with spells, and let ’em have it. The Monk’s belt can replace the AC Bonus if you want, though it’s ultimately not really necessary. Cleric also adds Righteous Might as an option for size-increasing, and it’s a rather good one (though not as good as Expansion).
If you really want, the Sacred Fist (Complete Divine) advances both Monk and Cleric class features. It’s OK enough, but I’d probably try to enter as a single-classed Cleric rather than a Cleric/Monk.
Swordsage
The Swordsage (Tome of Battle) is everything the Monk should have been to begin with. They get the same AC Bonus, except they can also wear Light Armor. Their maneuvers allow them to be a real martial artist, instead of just Flurrying (and missing) every chance they get. There’s even a maneuver or two that replicate Flurry.
The Unarmed adaptation of the Swordsage also gets the Monk’s Unarmed Strike damage, in exchange for his martial weapon and light armor proficiency. The Shadow Sun Ninja also advances Monk class features if you have them, but as the name might suggest it’s not really your typical monk-type class.
Best Answer
Introduction, Summary, and How to Read This (i.e. Not All at Once)
This answer basically covers a lot of potential options for Factota, not all of which are even that good. The basic premise is, Factota generally come in 1, 3, 8, or 20 levels. Factotum 1 or 3 can be added to a lot of builds. Factotum 20 is pretty straightforward, and works well.
The tricky part is Factotum 8, to take advantage of Cunning Surge on some other type of character. The best options for this seem to be:
Ardent, Psychic Warrior, or War Mind – for hustle, and general awesomeness
Assassin, for Int-synergy, spells to use with Cunning Surge, and good damage bonuses.
A martial adept, pact magic, or incarnum class, since these systems just multiclass elegantly.
Chameleon, for increased versatility, but note that Chameleon and Factotum conflict more than they synergize.
Iaijutsu Master,* for rather considerable damage output. Suffers badly on versatility though.
Possibly with dips in Cleric, Shadowdancer, or Swashbuckler to taste. Dips in the above classes also work well. This is all discussed at length at the end of this answer.
Reading this Answer
This answer begins with a discussion of the four main options for Factotum levels: 1, 3, 8, and 20. It then covers a bunch of Feats that many Factota find useful. Finally, other options for multiclassing on a Factotum 8 are discussed at length.
How Many Levels?
Factotum is most useful for 1, 3, 8, or 20 levels. It’s also, hands-down, the best “other class” in a Gestalt game.
One-level Dip
Basically, you’re doing this for the “all skills are class skills” thing. For the purposes of max skill ranks, once a class skill means always a class skill, so if you have Factotum 1, you can max out any skill in the game. If you have the Human subtype, the Able Learner feat (Races of Destiny) allows you to buy cross-class skills for 1 skill point per rank, like class skills, which means that a Factotum 1 with Able Learner can treat every skill in the game as a class skill for his entire career. This is not a bad use of a level and a feat.
You’ll barely use Inspiration Points, so don’t worry about them.
Three-level Splash
Factotum 3 gets you Brains Over Brawn, which adds Int to all Str-or-Dex-based skill and ability checks. That’s a lot of skills, and furthermore Initiative is explicitly a Dexterity check, which means you get to add Int to that, too. Very, very solid ability.
Able Learner remains a good choice here.
You have a little bit more use for your Inspiration Points, but nothing huge. Again, not a great concern.
Eight-level Swim
Cunning Surge (Factotum 8) is one of the best class features in the game. The ability to get an extra Standard Action in a turn is very rare, and for very good reason. Combine it with hustle, and you could get two full-attacks in a single turn, a feature usually reserved for high-level martial initiators (time stands still is the 9th-level Diamond Mind maneuver, Island in Time is the capstone of the Eternal Blade prestige class). It also allows great use of spells and other features.
The problem is that Cunning Surge requires a lot of Inspiration Points (and at this point, it’s not the only thing you’ll want them for). The answer here is Font of Inspiration, a feat that can be taken repeatedly, and grants Inspiration Points quadratically with respect to the number of times you take it. If you are only going for Factotum 8, you’re going to want a lot of this feat.
Able Learner is a bit more debatable for a Factotum 8 – at this point, you should have the 5 or 8 ranks you probably want for some of the more obscure skills, so you probably won’t need cross-class skills from wherever you go next, or might do better with other ways of getting them in-class, that have other side-benefits.
Twenty-level Marathon
Factotum is a great class. It is totally viable to take 20 levels of it. You have tons of class features, and with twenty levels, you do not need Font of Inspiration so much. It’s still a great feat, but you may need those feats more badly for something else. Able Learner, of course, is completely pointless to you.
What you do need is a source of damage. Cunning Strike does not, by RAW, stack with itself, and even if you rule that it does, you’ll burn a ton of Inspiration Points that way.
The best solution is to use the Gnomish Quickrazor,* an Exotic Weapon from Races of Stone. This weapon automatically resheathes after an attack, which means you can use it with Iaijutsu Focus,* a skill from Oriental Adventures that can give you extra damage on your first attack after drawing a weapon. You still need to make your target Flat-footed, which is harder than simply denying its Dex bonus to AC, and the damage caps at +9d6, but a Factotum is not a primary combatant: this is just enough to keep you relevant in combat.
Important Feats
These will vary based on how many levels you will take, what other classes you use, and so on, but some common feats used by Factota:
Font of Inspiration
This feat, from a web enhancement, is one of the most divisive feats for the Factotum. It grants you Inspiration Points equal to the total number of times you’ve taken the feat. So the first time, it’s just +1 IP. The second time, it’s +2 IP, so you get +3 total. The third time, it’s +3, and you’re up to +6 total. As a result, your Inspiration Point gain is quadratic with respect to the number of times you take Font of Inspiration.
A single Font of Inspiration is not worth it. Two is not really a great choice. Three is now taking a lot of your feats, but you’re getting a lot of return on that. More, and you get a lot of Inspiration Points from it. The question then becomes, how many Fonts do you need?
With only 1-3 levels, Font of Inspiration is of only dubious utility. The best class features at those levels don’t require Inspiration Points.
With a full 20 levels, Font of Inspiration is nice, but your base Inspiration Points is already pretty good. If you take it at all, take at least 3. Three feats is an awful lot, though, and pure Factota are definitely looking to give themselves more abilities with their feats.
If you break at exactly Factotum 8, you are looking to use Cunning Surge a lot. To do that, you need a ton of Inspiration Points. So you’re looking at taking literally as many Fonts of Inspiration as you possibly can.
If you are single-classed, but expect to play at only mid-ish levels (from roughly 6-14 or so), three Fonts of Inspiration is probably the sweet spot. If you are Human (which is desirable here), grabbing two at level 1 can get you pretty far.
Able Learner
Cross-class skills have two drawbacks:
They cost 2 skill points per rank
They are capped at half the usual max for class skills
However, these two drawbacks function differently with respect to multiclass characters. For rule 1, the cost depends on whether or not the skill is in-class for your current class, while for rule 2, the max depends on whether or not the skill was in-class for any of your classes.
Any character with one level of Factotum, in other words, has the class skill max for every skill in the game, even when he takes other classes, so rule 2 is covered and you only need concern yourself with rule 1.
Happily, Able Learner from Races of Destiny fixes rule 1 – it allows cross-class skills to be taken at 1 rank per skill point. It doesn’t do anything about the maximum, but as already explained, Factotum 1 handles that.
Able Learner does require that you be a Human or Doppelganger, but Races of Destiny explains that any race with the (Human) subtype should be able to qualify as a Human. Changelings from Eberron Campaign Setting are effectively half-human, half-doppelganger; the rules do not mention it but I have yet to meet a DM who would ban it from them.
Exotic Weapon Proficiency (Gnomish Quickrazor)*
This weird weapon from Races of Stone is used by flicking it out of its sheath, attacking, and resheathing it again immediately. This motion requires Exotic Weapon Proficiency, and the weapon gives you penalties if you use it without resheathing it. It grants bonuses to concealing the weapon.
Meanwhile, Iaijutsu Focus is an extremely obscure skill from Oriental Adventures; aside from the Factotum, only a few classes specific to that setting (such as its version of the Samurai) get it in-class. The way it works is, when you attack a Flat-footed target immediately after drawing a weapon, you roll an Iaijutsu Focus check and deal bonus damage based on the result. The damage varies from 1d6 to 9d6.
This is most likely the best source of damage for pure Factota, and not a bad supplemental to any Factotum who took Able Learner. Multiclassed Factota do tend to be feat-starved, however, so the EWP feat for this should be considered carefully. Since most Factota are not starved for skill points, it’s not an awful idea to throw points in Iaijutsu Focus even if you lack the quickrazor; you can get the damage bonus once, at least.
Knowledge Devotion
This feat from Complete Champion is pretty simple: make a Knowledge check, get attack and damage bonuses against creatures of the type(s) covered by that skill. You’re a Factotum, so something is seriously wrong if your Knowledge checks aren’t excellent. The damage isn’t as good as Iaijutsu Focus, but they stack and Knowledge Devotion is more reliable anyway.
Note that you can get this for basically nothing by taking Cloistered Cleric 1, and trading its free Knowledge Domain for this, as per the Complete Champion rules for Devotion feats. Unlike most Devotion feats, though, Knowledge Devotion is not fueled by Turn/Rebuke Undead, which makes it perfectly viable even for a pure Factotum.
Darkstalker
Factota have a lot of skills. Skill-monkeys are traditionally stealthy, and Factota can certainly do that. Anyone with an interest in not being seen really should take Darkstalker (Lords of Madness) – in one feat, it eliminates a lot of the “automatic” ways of spying on you. Make those Hide/Move Silently ranks count!
Other Classes
If you’re not a single-classed Factotum, you must have some other classes. Here are some decent options:
Swashbuckler
Swashbuckler 3 (Complete Adventurer) gets you Insightful Strike, adding your Intelligence to your damage. Damage is one of the few things you don’t get your Int to, so this is a good idea. More than three levels is not recommended, however.
Wizard or Psion
These classes allow you to make great use of Cunning Surge, and use Intelligence even more than a Factotum does. Unfortunately, losing three spellcasting levels for Brains Over Brawn hurts a lot, and losing eight for Cunning Surge is torture. Note, however, that if you’re playing a Gestalt game, this goes from a mediocre idea to one of the most powerful combinations in the game.
Sadly, these classes also lose a ton of skill points.
Cleric
Cleric spellcasting synergizes with Factota even worse than Wizards or Psions; the class is not worth taking for a Factotum looking for spellcasting.
What the Cleric does have, however, is Domains, which can, per Complete Champion, be traded for the excellent Devotion feats. You can even take the Cloistered variant from Unearthed Arcana for a free Knowledge Domain that can be traded in for the fantastic Knowledge Devotion. It also gains Turn or Rebuke Undead, which can be used to fuel the also-excellent Divine feats from Complete Divine, Complete Champion, and elsewhere. Plus, you do get some spells as long as you’ve got Wis 10, and even if you haven’t, they’re on your spell list so Spell Trigger items (read: Wands) no longer require a Use Magic Device check for you.
And all of this can be gotten for one measly level. Dipping Cleric 1 is so good, in fact, that it has an entire handbook devoted to it (the handbook is sadly down, along with all of BG, at the moment; let us all hope it will be restored).
The best options include Animal Devotion (several good options, including flight), Knowledge Devotion (damage based on your Knowledge checks – which ought to be stratospheric with the Int and skills you’re rocking), Travel Devotion (move as a Swift Action, letting you get a full-attack even while moving), Magic Domain (now all Cleric and Wizard wands are usable without Use Magic Device), and any Domain that hands you a feat you were looking for (and the options are quite broad). Trickery Devotion is also excellent. This list is a reasonably-comprehensive list of all the Domains and their benefits.
Beguiler
A base class from Player’s Handbook II. Largely in the same boat as Wizard or Psion, but with much better skills. Still not a great idea, and really a Beguiler is just not as powerful as Wizard or Psion, but by the same token you lose less by missing out on so many levels. It’s still too many, though.
Worth noting: if you’ve got Able Learner, EWP (Gnomish Quickrazor), and are going with the Iaijutsu Focus thing, Beguiler does get the ability to Feint as a Free Action if he’s got Improved Feint. That’s four feats (three if you can get Improved Feint as a bonus feat without needing Combat Expertise) and fourteen class levels, though.
Duskblade
Another base class from Player’s Handbook II, the Duskblade is interesting in that it gets to channel touch-attack spells through weapon attacks. It’s a pretty solid trick, though overall the class gives up a lot.
If you got 21 levels, Duskblade would be a lot better: Factotum 8/Duskblade 13 gets both Cunning Surge and the full-attack version of Channel Spell. Without that, Duskblade seems kind of lack-luster. Your spells are already well short of a full-caster, and you’re only falling (much) further behind by taking so many Factotum levels. Even with 21 levels, unless you’re starting there, you’ll have a long slog through mediocrity to get that cool feature.
Archivist
Like the Cleric, Wizard, and Psion, an Archivist (Heroes of Horror) loses a lot by taking enough levels of Factotum to get Cunning Surge (which is the only Factotum class feature good enough to warrant consideration for a full-caster, from an optimization standpoint). However, Dark Knowledge is like a better version of Knowledge Devotion (which you can also take, of course), which makes a Factotum/Archivist an interest idea for an Int-based gish-type. Probably even better than the Factotum/Duskblade, considering that Cunning Surge plus full-attack Channel Spell is impossible pre-Epic. Also is probably more enjoyable to “play through” than the Factotum/Duskblade.
Ardent, Psychic Warrior, or War Mind
Basically, hustle pairs really well with Cunning Surge. Two standard and two move actions per turn is amazing, really. And, of course, these classes really do not suck to begin with. All three are Wisdom-based, which is something of a shame but not the end of the world.
Psychic Warriors and War Minds (both Expanded Psionics Handbook) get hustle as a 2nd-level Power. Both get those after 4 class levels. Psychic Warriors don’t have prerequisites, and get more (but lower level) Powers Known and bonus feats (either Fighter feats or Psionic feats, which is a great list). War Minds get full BAB, higher-level (though fewer) Powers Known, more Power Points, and the excellent Sweeping Strike feature. Also note that War Mind caps at 10, which means a Factotum 8/War Mind 10 has to figure out what it’s doing with the other two levels.
Ardents (Complete Psionics, one of the few good things in the book) can get hustle with just two class levels, since it’s on the Freedom Mantle as a 3rd-level Power, and Practiced Manifester allows you to add up to +4 to your Manifester Level, provided it’s less than your HD. So a Factotum 8/Ardent 1 takes Practiced Manifester (Ardent), has an Ardent Manifester Level of 5, and then qualifies for Hustle at Ardent 2, due to the unique way Ardents get to select their Powers. However, it then costs him 5 Power Points rather than 3 for the Psychic Warrior or War Mind.
Ardent grows a bit better, too, actually gaining a single 9th-level Power at Factotum 8/Ardent 12 (Ardent Manifester Level 17). The Ardent also gains dramatically more Power Points than even the War Mind, and the Ardent 10 alternate class feature Dominant Ideal is incredible. However, without Mantle Substitution (described in the same Web Enhancement as above), the Ardent misses out on a lot of key combat-oriented powers that the Psychic Warrior gets. Even then, if you’re mostly just after hustle, having to pay an extra 2 Power Points per manifestation is a big deal.
Rogue
Rogues get even more skill points per level than Factota, and Sneak Attack shores up a serious flaw in the Factotum. A couple of levels for real Sneak Attack and the Penetrating Strike ACF from Dungeonscape seems quite nice, since so much of your potential damage is precision damage that doesn’t work on so many types of creatures. More levels are certainly viable, though personally I think Cunning Surge is somewhat wasted on Rogues. Rogue may be a better option for a Factotum 3 than it is for a Factotum 8.
Assassin
Assassin (Dungeon Master’s Guide) hits a lot of high points for you: it’s Int-based, it grants some spells which gives you good use of those extra Standard Actions you’re getting, and it gives a much better solution to that damage problem than Iaijutsu Focus (though, of course, you could – and probably should – go with both). It truly has a lot to recommend it here.
I’d definitely want Spell Compendium, though, since the DMG’s spell list for Assassins leaves a lot to be desired. Spell Compendium adds a lot of very nice spells.
Note that the Avenger does exist for those who find the Assassin’s fluff prerequisites difficult to meet.
Shadowdancer
Shadowdancer 1 is not a bad choice for the very high-quality version of Hide in Plain Sight. Best when combined with, e.g., Assassin. The rest of Shadowdancer is OK, but not great.
Binder, Crusader, Incarnate, Swordsage, Totemist, or Warblade
These classes simply multiclass well. The Warblade, in particular, is Int-based, and going Anything 8 (like Factotum!)/Warblade 1 allows you to take with 3rd-level maneuvers and stances from Warblade 1 due to the way Initiator Level works. Swordsage is a good choice for the same reason; starting with 3rd-level stances allows you to get Assassin’s Stance for +2d6 Sneak Attack.
Pact Magic (Binder) and Incarnum (Incarnate and Totemist) are simply multiclass-friendly subsystems, which means a Factotum 8/Binder 12, Factotum 8/Incarnate 12, or Factotum 8/Totemist 12 are all great ideas. Binder and Incarnate make excellent skill monkeys, while Totemists can make devastating melee shredders.
You could even combine these in interesting ways: Factotum 8/Swordsage 1/Shadowdancer 1/Assassin 10, for example, gets Cunning Surge, a whole bunch of maneuvers, Hide in Plain Sight, 8d6 Sneak Attack (and potentially 9d6 Iaijutsu damage), Assassin Spells, and Death Attack. That’s quite solid. Replacing Swordsage with Cleric for Knowledge Devotion and Travel Devotion might be even better.
Binder is from Tome of Magic.
Crusader, Swordsage, and Warblade are each from Tome of Battle.
Incarnate and Totemist are from Magic of Incarnum.
Iaijutsu Master*
This prestige class from Oriental Adventures is one of the few classes that’s actually written with Iaijutsu Focus as an explicit class skill. It gets Int to AC, which a Factotum will always like, but only while unarmored, which is less good. Cha to Initiative goes nicely with your Int to Initiative, and it also gets Cha to damage per Iaijutsu Damage die at Iaijutsu Master 5, which is pretty awesome. The remaining abilities (One Strike, Two Cuts at Iaijutsu Master 8 and Strike With No Thought at Iaijutsu Master 10) are both good, but both require that you use a katana, which is still worse than the quickrazor for the purposes of iaijutsu.
Actually, the ideal use of this might be a Factotum 8/Iaijutsu Master 10 that has a katana in one hand, and a quickrazor in the other: use the katana to start the fight (using Strike With No Thought), take full-attacks with the quickrazor, and then make a pair of attacks with the Cunning Surge standard action (using One Strike, Two Cuts).
The other option is to attempt to use an aptitude quickrazor (aptitude is a special weapon ability from Tome of Battle), but that’s pretty cheesy.
Chameleon
This very weird prestige class from Races of Destiny is incredibly flexible. It can fight, it can trapmonkey, it can cast divine spells, it can cast arcane spells, changing all these things around every day. It requires Able Learner, a feat that multiclass Factota love. Sounds a lot like the Factotum, no? And sure enough, the two are frequently paired together.
Personally, however, I find that the two classes are trying to do the same thing from slightly different angles, and they don’t synergize as nicely as you’d like. For one thing, Factota want to hit 8 before leaving, so they can get Cunning Surge, while Chameleons want to hit 2 ASAP to get the excellent Floating Feat (i.e. a feat you can change every day).
So unless you’re starting at 10th level, and thus can be a Factotum 8/Chameleon 2, I probably wouldn’t bother. Ideally, you’d be at more like 18th: Factotum 8/Chameleon 10, or perhaps Factotum 8/Chameleon 2/some spellcasting prestige class 8, if you can convince your DM to allow it. But at ECL 18... the benefits of these two classes at those class levels are a bit lackluster. It’s definitely viable, but I don’t think it works as well as a lot of people claim.
In short, as a Factotum you don’t want to give up Cunning Surge, and as a Chameleon, you don’t want to delay your class features. These two desires conflict very strongly, and no satisfactory resolution exists. You simply have to bite the bullet on it.
Ur-Priest, and similar
Ur-priest from Complete Divine is a 10-level prestige class, that gets 9th-level spells off the Cleric list. Yes, that means you can be a Factotum 8 – have Cunning Surge – and still get 9th-level spells. Yes, this is absurdly good.
I’m not aware of any class that has this sort of feature, and depends on Int,1 but for what you’re getting a little dual ability dependence is a small price to pay.
Really, I don’t recommend this. Yes, by being a Factotum 8, you delay Ur-priest and the like to the point that you don’t get 9th-level spells before a straight Cleric, Druid, or Wizard would, but any one of those classes would gladly delay their 9ths by a single level for the sake of getting a free better-than-Quicken on every freaking round.
Though I will say that if you actually manage, say, Changeling Factotum/Bard/Sublime Chord/Recaster/War Weaver (where you actually get Cunning Surge, 5 levels of War Weaver, and 9th-level spells), I will be impressed. That is one stylish and (absurdly) powerful build right there. I don’t think it’s actually possible though. (Sublime Chord is from Complete Arcane, Recaster is from Races of Eberron, War Weaver is from Heroes of Battle)
1 Beholder Mage (Lords of Madness) might, but that’s one of the top three most broken classes in the game (along with Illithid Savant – also Lords of Madness – and Tainted Scholar from Heroes of Horror), so... don’t do that. Any reasonable entry means cheesing your way around the Beholder requirement, and the only thing you’re likely to gain by doing so is some blunt force trauma.
* Caveat on Iaijutsu Focus
There are DMs that do not allow Iaijutsu Focus for whatever reason. Plenty also object to the use of the Gnomish Quickrazor, and admittedly, the combination of these two things was almost certainly not intended. Plus, Oriental Adventures is 3.0 material. However, despite this, I’d argue that such DMs are making a mistake, for the following reasons:
The pure Factotum is going to have a difficult time significantly affecting combat without it. No, the Factotum should not be a mainline combatant, but without Iaijutsu Focus they come close to having no effect, which is not good for the game as a whole.
It is not an ability that is in any sense "free," requiring as it does a feat, a maxed skill, and a special weapon, not to mention how difficult it can be to apply. Flat-footed status is decidedly non-trivial to achieve. A pure Factotum is going to spend a lot of combats burning Inspiration Points to Cunning Surge and use Arcane Dilettante to force foes to be flat-footed, and then have to use a full-attack to apply the Iaijutsu Focus repeatedly – just to almost keep up with the Rogue.
3.0 material is legal for 3.5 if it has not been updated – but Oriental Adventures stuff has been, in Dragon vol. 318. Iaijutsu Focus explicitly continues to function as it did originally.