FUTURE TIMELINE - SPOILER ALERT

One of the three core protagonists of the Keyholders' Legacy spinoff and was meant to play a prominent role in a third arc called Eternal Snow.

Bio:
An only child raised in a Keyholder family. He is in training as a Keyholder.
Blunt and short-fused, Hideo isn't afraid to face down anyone, and his tongue gets him into trouble. His temper aside, he isn't a bad guy to have around. He's resourceful and quick to pick up practical know-how. He always tries to see the way out of difficult situations to protect his fellow Keyholder trainees.

Relationships with other OCs:
Kaori - His cousin and fellow Keyholder trainee. He likes to push her buttons, so they're always arguing.
Toki - His aunt. He isn't around her a whole lot, but she seems kind of doting.
Reka - His uncle. He isn't around him a whole lot, but he seems nice.
Atsuko - His mom. She's the disciplinarian.
Toshirou - His dad. He's really fun, and they do a lot together.
Nikkou - His fellow Keyholder trainee. He's a bit of a mama's boy, but overall, they get along well.
Takumi - His teacher. He has such a stick up his butt.