Nemesis (To Love-Ru)

Nemesis, also known as Master Nemesis, is the main antagonist in To Love-Ru: Darkness. She is a bio-engineered weapon, like Golden Darkness and Mea Kurosaki, but does not share their genetic origins. She is a cruel, cold and heartless, under the mask of an innocent child person, she's a psychopath that shows no respect for any life in the universe.

The Guardians of Cosmictopia
Nemesis is one of supporting antagonists in Cosmictopia. She enlists the assistance of several villains and became the leader of League of Villains/Legion of Doom. With them, villains can "unleash the greatest power in the Multi-Universe and make villain-kind's greatest wish come true". What these are, however, has not been confirmed.