A special type of Lunarian that starts out as a giant, towering humanoid with six arms, but when attacked, it divides up into smaller and smaller forms; it eventually splits into 108 adorable, fluffy creatures resembling small dogs. When its parts are gathered back together, it goes back to its original appearance.

Shiro acts very much like a dog in all of its forms, and mysteriously, it seems affectionate and obedient towards Kongou.

It is later revealed that Shiro is the soul of a dog that Kongou and Dr. Ayumu once cared for together.