Kisaragi Gorou
如月五郎 On the Blu-Ray, his name is spelled "Goro".
A character on Kamen Rider Fourze
Played by Yana Nobuo
History
Kisaragi Gorou is Gentarou's grandfather and legal guardian, as revealed in Episode 27. He is a bike mechanic who had to move a lot due to his job. He takes Gentarou in after his parents are involved in an accident when he's in third grade.