Think about the real world
There are many conflicts in the real world, for many reasons. Look at news or a history book if you need inspiration. Not all of them are combat encounters, many might be detective work and exploration.
- Which church is allowed to tax/get the tenth in a village? Help the priests of Pelor against an attack by Asmodeus' children (insert $LOCAL_DEITY).
- Are there racial tensions between the races? Calm the mob of elves wanting to burn all halflings.
- Who illegally hunted a deer in the baron's forest? Free the arrested farmer or help prove his innocence so he won't be executed for his crime.
- A landslide destroyed the crop in the neighboring village, and they are running out of food. But giving them food from this village might lead to starvation in winter.
- A Party member is unfairly accused of theft. The punishment is cutting off the left hand. Fight the guards? Escape the guards (Skill challenge?) Prove innocence (How?)?
But much more important than the exact back story is in my eyes:
Make combat encounters diverse
It's not (only) the creature selection that makes an encounter interesting, but how you set up the battle. Let me make an example, with the same old 'bandit take village hostage' in three variations. I'm sure if you run it like that, the players won't complain it's always the same.
Devious, planning ba...ndits
The bandits have obviously heard of the wandering band of do-gooders and are prepared. First, they send in the dogs. Use skirmisher dogs that charge + make the enemy prone. Feel free to give them half HP or make some of them minions in order to make the battle shorter, but use enough different dogs they can't be locked down.
The dogs are backed by ranged attackers on the roofs behind chimneys - that means ranged attacks from cover, plus potentially combat advantage if they hid well. To get on the roofs, require at least a move action + athletics check. You can also make them minions, or at least some.
After two rounds, when the party is likely to be softened up, send in the Hog-Brothers, two large, burly fighters, brutes that will focus on the same target to make it go unconscious...
Trees are fun
Bandits have taken over the village, but the village is on a hill. When the party approaches, the bandits roll logs (trees) down the hills. That's a nice trap against Reflex that damages, secondary attack against Fortitude that slows. Once the party is up the hill, use charging brutes that push them down again. As always, use cleverly distributed archer minions to make it more dangerous.
Hostages
Again, bandits take over the village. Everyone is on the village square. When the party arrives, two bandits in the center threaten the peasants that were rounded up. Can the party lock down the two bandits and prevent an all-out slaughter, while fending off the other bandits? If you make the villagers run around frightened on the battlefield, you have another nice restriction: non-friendly area attacks kill peasants.
Build up a villain/villains
Don't worry too much about 'same backstory' for side encounters, it doesn't really matter as long as the fights are interesting. And you could build up a gang of bandits that terrorize the area... every session there's another gang-related side encounter. With time, the bandits also start hunting the party. This could tie diverse and interesting encounters together. Build one or two lieutenant for every side fight that has special capabilities (not magic, but either some leaderish/controllerish powers or a especially hard brute/soldier.
There actually is a level 10 Solo named The Risen King, in Fortress of the Yuan'ti pg 16, but he's a controller and poison/snake themed, which doesn't fit the Leoric concept very well.
Malachi's Butcher, from Dungeon Mag #163 pg 83, brings a different iconic Diablo undead boss to mind, so is also mostly un-helpful here, but he gave me an idea, so let's walk through the process of stealing his Spawn Meat Mote power, and applying it to a level-reduced Kas of Mondahan, who is originally printed in Dungeon Mag #170 pg 55, and was reprinted as Kas the Betrayer in Open Grave pg 204 with some math tweaks that don't really come into play after we de-level him from 26 to 11.
Kas has the following things going for him:
- A Bastard Sword
- A cleave power
- Regeneration
- The soldier template, which gives him high HP and high AC.
- A movement power, which we'll convert from flying to teleportation
- A healing-on-hit power, which we'll allow him to recharge.
I'm removing his dominate, because it's decidedly un-Leoric, and in its place I'm putting in that Spawn Meat Mote power I stole from the Butcher, only spawning a Skeleton Soldier (Open Grave: SotU pg 77) instead of a Meat Mote (they're both minions. Feel free to level up the Soldiers a bit, as the level 6 versions defenses are a tad low -- but Leoric's minions are cannon fodder, easily replaced and highly expendable, so I don't mind this at all.) A slightly stronger option would be Skeletal Legionaries from the Monster Vault, pg 257. These are level 7 minion soldiers.
I am also removing his fire resistance, climb speed, and mist-form, changing his training in Arcana and Stealth to Athletics and History, and giving him immunity to Daze and Dominate. Some of these are to more strictly adhere to Leoric canon, while those last two immunities are more because Solos desperately need all the help the can get in keeping clear of status effects.
I'm changing his mark-punishment from dealing ongoing necrotic damage to another means to summon a minion. In-play, this should work out fairly similarly to the ongoing damage, but consider changing the duration of the mark itself to save-ends, or removing the "this effect can trigger only 1/round" qualifier, if you want it to be more potent. As is, there's a fairly weak give/take between the two minor action options, with one definitely summoning a minion at the cost of 2% of his health, and the other maybe summoning a minion, without a health cost.
I'm also changing the condition upon which Regeneration is disabled. Sunlight implies that the original was a Vampire. Instead, let's make it stop working for one round after being hit with a Radiant power. This gives the paladin a reason to do the happy dance, and potentially gives the invoker interesting choices to make, given how many minions will be afoot.
After leveling him down to 11 (Level+4), this nets us:
Kas of Monadhan, the Skeleton King
Medium natural humanoid (undead)
Level 11 Solo Soldier
XP 3000
Initiative +8
Senses Perception +10; Darkvision
HP 440; Bloodied 220
Regeneration 20 (regeneration doesn’t function the round after Kas is hit by a Radiant power)
AC 25; Fortitude 26, Reflex 21, Will 26
Immune disease, poison, daze, dominate; Resist 10 necrotic; Vulnerable 10 radiant
Saving Throws +5
Speed 7
Action Points 2
Standard Actions:
Bastard Sword (standard, at-will, MBA) Weapon
+16 vs AC; 1d10+14 damage.
Blood Drain (standard; requires combat advantage against the target,
recharge 6) Healing
+16 vs Fortitude; 2d10+14 damage, and the target is weakened (save ends), and The Skeleton King regains 50 hit points.
Betrayer's Whirlwind (standard, at-will) Weapon
Targets up to three creatures; +16 vs AC; 1d10+14 damage, and The Skeleton King slides the target 3 squares.
Minor Actions:
The Skeleton King's Challenge (minor 1/round, at-will) Necrotic
Close burst 5; targets one enemy; the target is marked until the end of The Skeleton King's next turn. If the target makes an attack that doesn’t include The Skeleton King as a target while marked by this power, a Skeleton Soldier appears in a square adjacent to them and immediately attacks them. This effect can trigger only 1/round.
Raise Skeleton (minor, at-will)
Effect: the Skeleton King takes 10 damage. A Skeleton Soldier appears in a square of the king's choice within 2 squares. It acts immediately after the king.
Triggered Actions
The Skeleton King's Recovery (free action when kas becomes bloodied)
All adverse effects affecting Kas end, Blood Drain recharges, and then The Skeleton King takes a standard action after the triggering action is resolved.
Regal Assault (immediate reaction, when hit by an attack by a target within 5; at-will) Necrotic
The Skeleton King teleports up to 5 squares to a square adjacent to his attacker and immediately attacks them with his Bastard Sword. If it is available, he may use his Blood Drain attack as part of this power. If The Skeleton King is bloodied, a Skeleton Soldier appears in the square The Skeleton King vacated.
Alignment Evil Languages Common
Skills Athletics +15, History +13, Intimidate +16, Religion +13, Endurance +12
Str 21 (+10) Dex 12 (+6) Wis 11 (+5)
Con 14 (+7) Int 16 (+8) Cha 23 (+11)
Equipment: bastard sword , plate armor .
I quite like this result. His damage isn't too massive, so feel free to tweak it, or give him more minions at the start, or even more HP. But he's pretty tanky between his healing and regeneration, and should be spawning 2-3 easily dispatchable minions/round, which should keep the invoker occupied, and he should almost always be making 2-4 attacks/round.
If your players are decimating him, you can adjust on the fly by deciding not to remove his regen on radiant powers while he's bloodied, or by doubling his Blood Drain heal while bloodied, or by increasing the recharge on blood drain to 5/6 or even 4/6 while bloodied, or similar adjustments.
If your players are having a terrible time (or if your melee characters have attack bonuses under 13 (which would hit him on a 12), consider dropping his AC a few points. Swapping him to a Brute template would be as easy as reducing his AC by 4 and adding 1d10 to all of his damage rolls.
Remember to use his skeletal minions to flank with to gain CA for Blood Drain.
I hope this was a helpful exercise in monster creation, regardless of if you use him!
Best Answer
The thing is, games where resurrection and/or healing are limited are advertised as such. The players know what they're in for, and this sometimes requires designing your character appropriately.
It also depends on their play style up to now. If they die sometimes, forbidding resurrection can cause them to feel as though they are being punished for saving the world. If they haven't died at all, there will probably not be a problem though. You might still have to take more care when designing encounters.
Whatever you decide though, you have to discuss it with the players beforehand. The game is meant to be fun, after all; if they don't like the idea, you shouldn't do it. You should also tell them what you plan for them to do if one of their characters dies. Do they roll up a new character? What level? etc.
Some ideas to 'soften the blow':
I don't think you should phase out dying completely though. That sounds a little boring.