I do love that whole future apocalypse stuff. Guns and power armor and stuff. But I also love magic! Yes you have necromancy, but from what I can tell it is not PROPER necromancy. We need to have the ability to posses your friends with demons! And brew strange potions with strange effects! Do rituals and stuff to get more magic! Find other wizards! Have sniper battles with fire balls! Limited mana so you can't spam too much! Levitate the your opponents! Or simply their weapons! Preferably not their clothing cuz, ew, dude, that's gross...
Of course this could easily get out of hand and stuff, so there can be balancing like for example, you slowly kill hurt when doing magic, thus putting on limits. Or maybe the magic spell could fail. You're trying to light a campfire when you instead like YOURSELF on fire!
Plus there can be new mutations/species! Such as a vampire or a werewolf. Maybe you were secretly a zombie all along! (You gave your soul to live) Or maybe your profession is to be a monster hunter!
New items like silver bullets! Plus stakes too. Don't wanna get to close to that vampire? try throwing your stake at them! It may-or-may-not work. If it doesn't and you still wanna stay away use a stake on a stick! Basically it is a stake attached to a stick for extra reach. Why is it that the stick can't be a stake? Because magic type stuff has rules bro.
A good place to find vampires is in graveyards or woodland mansions. Werewolves in the hills,er, forests aren't too rare. Zombies still don't like you if you are a vampire or werewolf tho.
Vampires have OP night vision. They cannot bleed and are less likely (but still possible) to get hurt from bashing damage. Big downside, you light on fire if you go into the sun! Canines will get aggravated wear nearby a vampire and deal extra damage to said vampire. Vampires naturally make little to no sound and have an ease at walking on all terrain, but unfortunately never managed to grow wings. Vampires can feast on blood to quench thirst, add a mood buff and temporarily gain several boost: speed, strength, dexterity, damage. (not stackable) Has a small chance to 'bite' an enemy when fighting if the mouth is not too encumbered, this gives a boost similar to drinking blood, but smaller. You can feed off of your followers in their sleep without turning them if you so wish. But there is a chance that the follower will wake up, and they'll most likely do so aggressively. If they like you enough they'll let you feed off them when awake! You can turn them into vampires also, but then you wouldn't have as good of a blood source since zombie blood is gross!
Werewolves have most of their effects only on at night. Canines will never attack them unless provoked. They always have a small boost in strength, dexterity, and speed, and have SOME night vision (but not as good as a vampire). They don’t get a debuff from cannibalism, but neither to they get a boost. At night (not specifically a full moon) werewolves turn into their beastly form. They deal decreased damage when wielding items due to their claws, but deal more damage without wielding anything. Their fun grants a little natural encumbrance and warmth, when in their wolf form they get a small mood buff for having no cloths on… (Well, wolves don’t wear cloths after all. And they are covered in fur!) Hearing is greatly increased also. Unfortunately, while you don’t ‘wolf out’ only on full moons, the further away from one, the weaker you’ll be! On a new moon you’ll be practically a normal human!