Lore

Elder Lich

死者の大魔法使い（エルダーリッチ）

Races & CreaturesMajor Races

An intelligent undead mage born when negative life inhabits the corpse of an evil magic caster; it is a middle stage in Ainz's racial lineage.

As a monster it is level 22; a platinum-rank adventurer team would struggle somewhat against it, while a mithril-rank team has a good chance of winning.
Appearance: withered bones with a bit of rotting skin, wrapped in a lavish but old robe and holding a twisted staff; its intelligence is far beyond an ordinary person's.
It has complete cold and electricity resistance and darkvision, but it cannot see through obscuring conditions such as mist.
In YGGDRASIL, a character can switch to this race with a "Book of the Dead" (Web novel comment reply: Skeleton Mage level 10+ with a Book of the Dead, or magic class level 30+ with specific books after completing an event).
Ainz's races: Skeleton Mage (starting undead race) 15 → Elder Lich 10 → … → Overlord.
In the New World, individuals surpassing Elder Liches are called "Night Liches" and can use 6th-tier magic (side story The Vampire Princess of the Lost Country).
Elder Liches (level 22) are stationed in the catacombs of Nazarick's 1st–3rd Floors; since the Sorcerer Kingdom was founded, Elder Liches have handled administrative work (Vol. 10)

Notes

The Web novel called it a "Lich"; the light novels changed it to Elder Lich; sources speculate this was for copyright reasons.