有川 譲

Underclassman that goes to the same school as the protagonist.  He was summoned to the parallel world along with the her. Masaomi's little brother.
One of the Hachiyou that protects the Priestess, the Byakko of Heaven.
He's had feelings for the protagonist for some time, but she hasn't noticed.
He acts mature for his age, but when he's concerned about the protagonist he can get nagging. 
However he is very reliable and in the end lenient, he's sweet with the protagonist.