Grandpa

Grandpa is Rio and Rick's grandfather.

Manga
Grandpa is only briefly featured in manga, helping Scar to heal from his wounds in battle against Gluttony and Lust.

Anime
Grandpa has larger role in anime, as Rick and Rio appear in more episodes then in manga. Aside from lodging Scar, he tells the boys truth about their mother and her death after their brief disappereance.