Leviathan

Leviathan is the name of an ancient cyber superweapon known by only a few individuals. It was sealed in the old laboratories of FLAK due to its extreme danger. Leviathan caused a great disaster eight years ago, resulting in the indiscriminate death of many civilians until it was sealed. Its abilities remain largely unknown, but those who witnessed it were deeply traumatized by its power. In Bachelor's route, it is unsealed by her to protect herself from Genha. In Ren's Route, it is revealed that Leviathan reacts to her emotions: the more negative they are, the less control she has over it, as it represents her subconscious.