Nemesis was the main antagonist of To LOVE-Ru Darkness, who later turned protagonist. She is the master of Mea. She first appears in shadow and talking to Mea only. Her main goal is to investigate the reason why Yami became more like a human and no longer try to act as an assassin.
In chapter 23, she finally appears in person and begins to tease Rito about his shyness and try to turn him into her servant.
Despite not getting along too well with Momo, they sometimes enjoy teasing Rito together.
Nemesis's main objective is to turn Yami into her darkness form and start a new galactic war in order to create a place where living weapons are suppose to live.
In chapter 60, she fights and is defeated by Gid Lucione Deviluke. As her body starts fading away, Rito decides to let her merges into his body in order to save her life.
She spends her time inside Rito's body for awhile and gains knowledge about Rito's past, memories, and his feelings toward other characters.
After she recovered her strength up to 75%, she is forced to separate from Rito's body to fight Kuro. However, Yami shows up to take on Kuro and finish the battle.
Nemesis then forcing her way into Sainan High as the new student council president. She declares in front of every student that she loves Rito and she wants to make him happy by establishing a harem for him. However, the plan fails in a very short time after Haruna confesses her feelings to Rito.