Saeyuku


 * "Underneath the blazing sun, a shimmering shadow" - Kai no Kimi

Saeyuku (冴え行く, Saeyuku; lit. "clearing gradually") is a former experiment of the to mold the tasks of the  into a more sentient and intellectual being, although the attempt was deemed failed because of Saeyuku's muteness, which limited him from carrying out his task of transmitting orders and messages. He was locked up in a cell containing a spiritual suppressor, preventing him from escaping out of it ever again.

Somewhere before the events of the Red Eclipse, captain of the 3d division Sōsaku Yawarakai came across Saeyuku and broke him out of his container, seeing potential to reshape his unique powers into a valuable weapon. Even after Sōsaku's defection, Saeyku has remained a trusted and loyal ally of him, if not to say the only one.