A private investigator and muscle for hire. He has bad luck and is seen having no jobs save for the unsuccessful and often embarrassing errands he is sent on by his only employers, Kanako and Yayoi. He is very competitive, to the point of racing and getting arrested just to win a bet against the Ark's owner.

Spoiler

Hideo is the son of a young boy that Arashi saves when she goes back in time with Hajime. Hideo remembers that a woman named Arashi saved his father, but does not realize that it is in fact the Arashi of the present is his father's savior. Without Arashi's help, Hideo would not have been born.