Shiro is the first son of the Amagiri household. During his training at a young age, he found that he was capable of manifesting multiple Devices and activating many Noble Arts. However, some members of the family saw him as an outcast that had no right to be called a Amagiri. This knowledge didn't deter him from his training; instead, he used this as a way to motivate him to reach his goal. And after learning of his eldest sister's disappearance, he has even more reason to become stronger. Now, they're both in Hagun Seidoukan Academy to show their skills as Genestella blazers.