Souichi Ayukawa

Soichi Ayukawa is Miyuki's grandfather and a skilled technician from the moon. Haruka revealed that he was formerly a mechanics professor there, possibly of some renown. Recently, it has been discovered that at one point in time he worked with Thousand and Yang Harris on researching Ultimite.

He was the founding creator of the Big Foots after years of studies of the Ultimite when he worked for Lunatic Corporations until he quit after the death of his son.

(Source: Wikia)