Momonga

A cautious and stingy person, Momonga always tries to plan and control details, avoiding any haphazard actions. Because he doesn't underestimate his opponents, he will usually overkill them. Since being transferred to a new world and becoming an actual Undead being, Momonga could feel himself becoming very cold and calculating, his emotions repressed.

Loyal to his friends and creations, since becoming Lord Ruler of Nazarick in the new world he acts with a certain degree of nobility for his devoted followers. Momonga only does things that will benefit Nazarick or himself, whether it's information or prestige. Although he does have a sense of justice and doesn't hate humans as much as his followers, he holds no attachment to them, and he feels nothing toward their deaths.

In the New World, he is the Sorcerer King of the Sorcerer Kingdom and the most powerful magic caster in the world. His other identity is famously known as "Momon," a dark warrior and leader of Darkness, an adamantite ranked adventurer group of that nation. He is an adamantite class adventurer and the strongest adventurer known in E-Rantel. His real name is Satoru Suzuki.

(Source: Overlord Wikia)