I'm considering playing as an undead themed overlord, purely for fun thematic reasons. I realize that most quests have fixed monsters, so I'm thinking of limiting the quests avaliable in the adventure path to those that have undead monsters to start with if possible. And in some cases I might even swap a fixed monster for a similar undead one, knowing that there's some risk that it will change the balance. For example exchange goblin archers for skeleton archers. Obviously I have the blessing of my gaming group to do this.

So, some questions:

Any suggestion on what campaign would fit the best for this theme? And which rumour quests?

I do not have all expansions (far from it) but I am considering Treaty of Champions for the skeleton archers. Are there any other expansions (both boxes, H&M packs) that I "must have" to get as many undead monsters as possible?

Also, what would be the most fitting agent for this? I'm considering Eliza or Alric, both of which I already own, but are there any other fun undead agents?

Lastly, what OL class would feel most thematic? And in what expansion can I find that one?

As I said, I have few expansion, and I don't want to buy them all. Therefore I'm looking for input and suggestions from you all.

I would start with a mini campaign like trollfens.... shadows of nerekhall could work.... really, I would create 3 or 4 quests in the quest vault to play a linear mini campaign (I will then be able to play it!)

I love that you want to build a game around your own theme!!

Guardians of Deephall has dark priests which would be cool to raise the dead... Manor of ravens have wraiths. The changelings from shadows look undead. Another recent hero and monsters has reanimates.

I would use all LT's that may have an undead theme... all of the farrows fit into this... tristayne Oliven and gargan mirklace are also necromancers....

Alzo... if you make your own quests, take the monsters we have and beef up their stats and ignore group limits... make a whole quest about dark priests raising zombies and have many many keep coming up until the ritual is ended......

If creating a theme seems like the most fun for you and your group, then keep theme first (story telling) and create some cool exploration type mini campaign in the quest vault.... do 4 encounters to stop the ever spawning zombies and zombie dogs (barghests... fast zombies)...

Also... to keep things dark, place a black table cloth under your tiles... play some background music... this isn't just another group of zombies to plow through, these are the npc villagers you met in the first encounter!.....

Ok... this was a ramble... good luck and if you make quests advertise them here!

From what I've played from it so far, Mists of bilehall seems the way to go campaign wise. It has the reanimates mentioned above, and the story starts out with the battling hundreds of undead in the mists..

As for lieutenant, I would have recommended the new Ardus Ix'Erebus since he is a walking skeleton as well, but he is one of the lieutenants in mists of bilehall, so that probably wouldn't work too well.

I think any of the Farrows would do as an undead agent, if you´re using Mists of Bilehall and don't want to pick a deck with one of the new lieutenants in that campaign.

Eliza is a vampire, Alric is dead and Merick I don't remember but he certainly does some necromancy stuff.

Also, monsters:

Zombies (Base Game)

Barghests (Base Game)

Reanimates (Mist of Bilehall)

Bone Horrors (Mists of Bilehall)

Skeleton Archers (Treaty of Champions)

Wraiths (Manor of Ravens)

Dark Priests (Guardians of Deephall)

Crypt Dragons (Guardians of Deephall)

The new expansion Mist of Bilehall pretty much features an undead themed campaign (only for Act 1 though), all with undead monsters (Skeletons, Bone worms and bugs that reanimate dead bodies) and so on. I heard it's a bit hard on the heroes though. Nevertheless it features the most undead monsters of any expansion (3) I can think of and costs only a little bit more than a H&M pack.

I'm going to insert a plug for the quest vault here. You have a pool of monsters from various expansions already. You can figure out a story you'd like to tell within that undead theme, and map out tiles using the expansions you're including. If you don't want to do that and would like to use pre-made quests, I second (third?) the recommendation of Mists of Bilehall- it's got several very cool undead monsters, as well as a good cryptlike/decaying theme with regard to tiles.

Thanks for all the suggestions!

While using the quest vault might be a fun idea, I think that I (at least initially) will use an existing adventure and slightly tweak them to use more undead monsters. While theme is fun we also want to keep the balance of the game, and I'm not sure my home made quests would be very good. But it's probably something I'll try in the future.

So it looks like Mists of Bilehall is the way to go, and maybe one of the suggested H&M packs. The mood music and black table I will definitly use.

Any thoughts on Overlord Class? Is there any class that has a undead/necromancer feel?

Can't really think of anything. Maybe the unkindliness deck from Manor of Ravens with the raven flock servant? You could say the ravens fed off the reanimated corpses and became corrupted that way or something

Awwww cool!!! I am glad you like the dark table cloth and music idea!!!!! Doing these little tricks from my rpg days is easy and adds alot!!!!