Ainz's Death Knight

Magic Resistance. The death knight has advantage on saving throws against spells and other magical effects.

Marshal Undead. Unless the death knight is incapacitated, it and undead creatures of its choice within 60 feet of it have advantage on saving throws against features that turn undead.

Once a Death Knight manages to kill its intended target, that dead body will later end up turning into an undead. For those killed by a Death Knight, their body reanimates as a Squire Zombie.

Multiattack. The death knight makes three longsword attacks.

Longsword. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 10 (1d10 + 5) slashing damage, or 11 (1d12 + 5) slashing damage if used with two hands, plus 18 (4d8) necrotic damage.

Parry. The death knight adds 6 to its AC against one melee attack that would hit it. To do so, the death knight must see the attacker and be wielding a melee weapon.