Kaname
Tōsen

Kaname Tōsen was the captain of the 9th Division and one of the three who walked out with Aizen. Blind since birth, he navigates entirely by sound and spiritual pressure, and his stated principle is to take the path with the least bloodshed. He repeats it often enough that the people around him take it at face value.

The origin is a friend killed by her own husband, a Shinigami who was punished with nothing worse than a demotion. Tōsen joined the Gotei 13 to carry her sword and spent his career watching a system he considered rotten fail to punish anyone. Aizen offered him a version of justice with an outcome attached, and Tōsen followed him knowing what the King's Key would cost in innocent lives, which is the contradiction the character never resolves.

Suzumushi builds toward Bankai as sensory deprivation: a black dome where nobody can see, hear, smell or feel anything except him, which levels the field to the one he has always fought on. In Hueco Mundo he takes Hollowfication further than any of them, and it gives him eyes for the first time in his life. He looks at Sajin Komamura and Shūhei Hisagi, the two people who never stopped calling him a friend, and the sight of them is what breaks him before their blades do.