Would being able to be a Good assassin mess up the game or something? Have the designers ever explicitly stated why they added that requirement to the class?
Secondly, is there an alternative?
[RPG] What are the ramifications of waiving the Evil requirement for the assassin class
assassindnd-3.5epathfinder-1eprestige-class
Related Solutions
That I am aware of, there is no official template
If there was, it'd be in The Book of Vile Darkness, or else one of the Fiend Folios. I'm sad to say that I don't believe there's a template that mirrors Saint in terms of flavor or mechanics.
But...
I can propose some adjustments for you. Try doing this to the Saint template:
Requirements: Swap the requirement for a Good alignment with a requirement for an Evil one. Swap the prerequisite Exalted feats for Vile feats, and require a great act of evil in the name of a dark god (personal suggestion: a sacrifice of good-aligned sapient beings equal to double the character's hit dice).
Numerical Bonuses: Swap all instances of "perfection" bonuses with "profane" bonuses in the same areas. You can probably leave the energy resistance alone.
Spell-Like Abilities: Check and see which of the SLAs are distinctly "good" and replace them with evil ones. Some of them can probably stay, however, so don't go too crazy here.
Everything else, if I remember correctly, can remain the same.
Prestige Classes
There's a couple of prestige classes that might be useful to you if the villain in question is a fiend (an evil-aligned outsider) - namely, Fiend of Blasphemy and Fiend of Corruption, both of which can be found in the various Fiend Folios. These prestige classes give powers that help the fiend to corrupt, debase, and destroy souls in the names of greater patrons (or just Evil Itsownself) and could be very useful in your endeavor.
The intent of the rule, IMO, is that an assassin gets a death attack on someone not expecting to get ganked by you. So being alerted that "there's a suspicious invisible guy over there" does indeed foil a death attack since it puts the target on their guard against you (even though "you" are not totally clear to them, your presence and square is and that's good enough IMO). You have to be either be undetected or alternately not recognized as a threat (the standard "disguised as a barmaid" gambit). Anything that would kick someone into "I'm about to get attacked" mode, much as it denies flatfooted sneak attacks, denies death attacks.
Some of this is GM discretion (horrors!). Is that noise suspicious enough that someone really is in "time to whip out their weapon" mode if they hear it? Does the guy get a Sense Motive when you sidle up to him in barmaid guise and are vamping him to set up the close range stabbing? As a GM I'd rule "unknown invisible guy" is probably a dead giveaway - unless you're in a wizard's club where everyone has an unseen servant, in which case maybe not...
The assassin in my Reavers campaign has gotten off several successful death attacks in these scenarios:
- The party saw a derro in a room and decided to hang back, he stealthed up and sneak attack/death attacked him
- He's gotten sniper death attacks in while hiding in the ship's rigging during a melee; he studies a guy engaged with other folks for three rounds and then pops him
- He killed a crewmate he had problems with at dinner
Now, invisible folks do get sneak attack even when someone knows they're there - I consider death attack to have a higher prereq though.
Best Answer
There are a lot of character options that have plot/alignment based restrictions. Almost all can be ignored by DM fiat, and many only apply to a very specific campaign world that you may or may not be using.
Many races have alignment restrictions, which is, lets be honest, a tad racist. Fantasy is full of examples of non-evil goblins (World of Warcraft), Ogres (Shrek) and Vampires (Team Edward!)
Classes also have some unnecessary restrictions. While most Barbarians will be chaotic, there is nothing to prevent a DM from creating a world where barbarians form tight-knit tribes of lawful aligned individuals. Arguably the Aiel in the Wheel of Time series would be significantly comprised of barbarians (and scouts, rangers), but they are certainly lawful aligned.
Paladins originally had lawful good as a restriction. That was later expanded to any of the 4 extremes with minor changes to abilities.
Other people have recommended doing away with alignment (restrictions). I would recommend keeping them, but adapting them to your campaign world.
Don't ask "is there any reason why I shouldn't allow a good assassin", instead ask "if there is a good assassin, who trained him?" Is there a good assassins guild? (avenger/slayer of domiel style). Or was the character once evil, trained with evil assassins and has since had a change of heart? If so, it's probably that the assassin's guild wants him dead, as do the various relatives of his innocent victims. I smell a side quest.
Don't worry about whether dropping alignment restrictions will impact the rules, but will it conflict with your plot?