Necrolyte (5e Creature)
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Medium undead, neutral evil
Saving Throws Con +6, Wis +1
Necrotic Absorption. Whenever the necrolyte is subjected to necrotic damage, it takes no damage and instead regains a number of hit points equal to the necrotic damage dealt.
Speak with Undead. The necrolyte can communicate with undead as if they shared a language.
Undead Resurrection. If radiant damage reduces the necrolyte to 0 hit points, it dies permanently. If it is reduced to 0 hit points by any other method, it revives in 1d4 turns with 1 less hit dice. If the necrolyte has no hit dice to use to revive itself, it dies permanently.
Multiattack. The necrolyte makes two attacks, only one of which can be a bite.
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 4 (1d4 + 2) piercing damage and 5 (2d4) necrotic damage.
Slam. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 5 (1d6 + 2) bludgeoning damage.
Necrolytes generally look like ordinary civilians with skin which is paler until they die. When they die they come back to life but with more of a rotted or decayed appearance which gets worse the more they die and come back to life until they just look like walking corpses.
Necrolytes are humanoid creatures who were infused with necrotic energy before birth which usually kills them and their mothers. If they are buried with their mothers they grow in the womb until they dig themselves out of the womb and the grave. After they are "born" they rapidly grow over the course of several months into a full-size necrolyte.