Ainz Energy Drain

Ainz’s specialty was necromancy, and this was an eighth-tier spell from that field, [Maximize Magic – Energy Drain]. It was a spell that drained the opponent’s levels and granted various benefits depending on the number of levels drained. Naturally, this spell had also been maximized.
He beat the Evil Lord’s spell resistance and drained his levels. Thanks to that, he recovered almost all the damage Yuri had inflicted. That said, the healing provided by this spell was only supplementary in nature.
Ainz’s parameters were all temporarily enhanced, and he received a special buff which would fade in a short time. In turn, the Evil Lord had received a level down debuff which could not be removed by the passage of time.

- Overlord; Vol 13; Chapter 5