Hibachi's grandfather (whose real name is unknown) is Hibachi only known relatives and a former ninja of the Chinpou style. He still trained even if ninja are no longer needed.
Hibachi's grandfather wear a traditional Japanese outfit and long hair that is tied up.
Haru's grandfather seem to be a warm loving grandfather to his granddaughter and only smile toward her. He still trained despite ninja are no longer needed. He is shown that he doesn't want Hibachi to inherited the family techniques due to being a female.
Not much is known about his past but he was a master ninja and trained Hibachi despite him not wanting her to inherit the family techniques.
Not much is known about his abilities but he might be a very skilled ninja.