Kirihara eventually learns Seras is working with Mimori and is convinced that Seras is somehow forced or tricked into this position and wants to save her, so she could be his fuck toy. Vicius lends him her ultimate defense bubble that blocked Mimori's attack on her first, and he goes to kill Mimori. During the confrontation, Mimori breaks the guy's reality by making him realize his delusions of grandures are just delusions. No one likes him. No one respects him. They never listen to anything he says. He is a worthless piece of trash, a waste of space. Kirihara is so enraged it lets him be open to a curse that breaks the dispell charm, allowing him to be paralyzed. Even then, he orders Seras to kill Mimori. Even Ayaka, who is present at this scene, is disgusted with him and lets Mimori use Freeze on him, ending Kirihara. He's not dead, but not alive either.