Advantages and disadvantages to give an undead PC or NPC

[MarkVIIIMarc]

A fiend, Maurezhi, my players' concern over what the curse was, the need to have a bad guy in charge of the Maurezhi's with a better/worse curse, having watched a lot of i-Zombie, hearing Rob Zombie on the radio and who knows what else has given me the idea to insert a curse/mechanic where an NPC and quite possibly a PC or two, willing or not, may become a reasonably functional if done right, intelligent, perhaps even free minded undead/demon spawn.

What advantages and disadvantages can I give an undead NPC/character w/o breaking the game?

-Zombies have inspired me so I'm thinking they must eat something sentient daily, weekly or however often or start suffering exhaustion and start decaying and losing intelligence down to an alive but incoherent and animalistic level.
-If the food has an intelligence of 6 so will the character because it isn't nourishing enough but they can't raise above their INT stat?
-Can't eat or drink regularly, more of a social thing if they are trying to blend in with Disguise Self spells.
-Disadvantage on Intelligence and Wisdom saving throws vs whoever turned them or that entity's masters.

+Can't suffocate
+immune to poison
+fire resistance as a fiend turned them (too strong?)
+Will fit in better infiltrating a portion of a hell which is a side quest I'm going to dangle

+/- Obviously looks different for social interaction. Could be scary intimidating easily. I'm imagining this to be a more radical obviously not right grey skinned/black hair look even more so than a drow or Liv from i-Zombie but not disgusting by any means and possibly even attractive in an evil way as long as they are eating regularly. I described the evil Maurezhi boss as an amazingly fit, sharp looking and charismatic elf demon/undead hybrid as he negotiated with the party.
+/-their healing spells work as heals on other undead and hurt the living?

?~Should I change the death saving throw mechanic for undead PC's? I'm thinking about making it where they pop up Zombie like on a Con saving throw of the damage dealt, otherwise need healed or 3 fails and you're out.
?~maybe has to or does not have to drink even much less eat regular food.

All suggestions are welcome. It was a long commute today.

(unless the party goes full blown crazy happy virtually asking or looking for or expecting it I'm avoiding the eat a brain get its memories thing)

[MagneticKitty]

There's a revenant pc race. Search unearthed arcana gothic heroes. I'd honestly change their race (ie they lose their old race benefits) and make a undead race balanced against other races.

[MarkVIIIMarc]

There's a revenant pc race. Search unearthed arcana gothic heroes. I'd honestly change their race (ie they lose their old race benefits) and make a undead race balanced against other races.

That does seem like a nice project. In another campaign I run the party is in a "wild west" area of sorts where they just may stumble into a town of undead now that you have me thinking about it.

This group is not super into paperwork.

I might just go with the list. I can be vague at first to. Like, "You have the urge to eat a dead corpse brain soon". "You feel drained from not eating, that Orc who's skull u just smashed open is sure looking tasty". "huh, the fire didn't hurt you as bad as usual, take 1/2 damage".

That way they get the idea w/o having to write a new character sheet or something.

[MagneticKitty]

Well if you don't want to swap out racial feats, I'd give them orcish resilience, as a non op substitute for undead fortitude.

Poison and fire are some of the most common damage types, if you give them resistances their should be heavy penalties. Maybe while they have this condition healing spells don't work on them. And they are vulnerable to radiant. And can be turned.

Blood lust: you no longer need conventional food. Instead you crave raw meat and blood.
You have a bite attack dealing 1d6 + strength necrotic damage, and healing the damage you delt. You may only heal a number of times equal to your constitution modifier with this ability. You regain all uses of this ability after completing a long rest. You must declare you're going to heal after the attack hits but before damage is rolled. If you do not heal in this way once per long rest you gain a level of exhaustion.

Describe their disgust for human food, and their hunger not being satiated by normal things. Maybe human food now smells bad to them, or they vomit it up.

In most stories undead hate fire. Especially frankenstein's monster. Doesn't feel like correct flavoring to me.

[MarkVIIIMarc]

Well if you don't want to swap out racial feats, I'd give them orcish resilience, as a non op substitute for undead fortitude.

Poison and fire are some of the most common damage types, if you give them resistances their should be heavy penalties. Maybe while they have this condition healing spells don't work on them. And they are vulnerable to radiant. And can be turned.

Blood lust: you no longer need conventional food. Instead you crave raw meat and blood.
You have a bite attack dealing 1d6 + strength necrotic damage, and healing the damage you delt. You may only heal a number of times equal to your constitution modifier with this ability. You regain all uses of this ability after completing a long rest. You must declare you're going to heal after the attack hits but before damage is rolled. If you do not heal in this way once per long rest you gain a level of exhaustion.

Describe their disgust for human food, and their hunger not being satiated by normal things. Maybe human food now smells bad to them, or they vomit it up.

In most stories undead hate fire. Especially frankenstein's monster. Doesn't feel like correct flavoring to me.

Drat, undead hate fire. They must have a terrible time when taken back to the hells by their masters. Or maybe they just get left here to mess with us.

Without the fire resistance I don't think I'm buffing them much at all except for the lack of need of air, but how often does that really come up so thats cool.