Nihilethic Zombie

Ghostly Body (Void Ghost Form Only). The nihilethic zombie has resistance to bludgeoning, piercing, and slashing damage from nonmagical attacks. In addition, the zombie can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

Undead Fortitude. If damage reduces the nihilethic zombie to 0 hp, it must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, the zombie drops to 1 hp instead.

Undead Nature. The nihilethic zombie doesn't require air, food, drink, or sleep.

Slam (Undead Form Only). Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage plus 7 (2d6) necrotic damage.

Withering Touch (Void Ghost Form Only). Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 8 (2d6 + 1) necrotic damage.

Void Shape. The nihilethic zombie magically transforms into a dark purple, Void ghost form or back into its Undead form. Its statistics, other than its speed and resistances, are the same in each form. Any equipment it is wearing or carrying changes with it. It reverts to its Undead form of it dies.

Sacrifice Life. When the nihilethic zombie's controlling nihileth takes damage while within 30 feet of the zombie, the zombie can send its life force to the nihileth. The zombie's hp is reduced by up to the amount of damage the nihileth took, preventing that amount of damage to the nihileth. If this damage reduces the zombie to 0 hp, it is immediately destroyed. A nihileth can benefit from only one zombie's Sacrifice Life for each source of damage it takes.

Void Body. When the nihilethic zombie takes damage that isn't radiant, it can reduce the damage by 1d12.