Hideki is a tol boi with brown hair and brown eyes.
Dad has a company. Lived by Mamoru and Takashi. Went to middle school with Doki. Mercenary group. Hacked into Future Foundation records in order to get into Hope's Peak.
Hideki is infatuated with Madoka.
- 1 - 3 Low - Average
- 4 - 6 Above Average - High
- 7 - 10 Extremely High - Perfect
- (Internally after a text) "QAGRFDS"
- (About Madoka stealing code) "You were way too interested and I totally saw it coming. Made my own copy as soon as it was finished."
- Hideki's given name uses the kanji 英 (hide) meaning "excellent, fine" and 樹 (ki) meaning "tree."
- Hideki's surname uses the kanji 石 (ishi) meaning "stone," and 川 (kawa) meaning river/stream.
- His blood type is AB.