Mr. Gaku is salesman for a company known as Kronos Heaven which specializes in making highly realistic robots, or “figures,” for various purposes. Though usually businesslike and down-to-earth, Gaku sometimes is not taken seriously and is frequently mistaken for a cosplayer because of his odd manner of dress. Every character refers to him as the "shady salesman." When Riiko cannot return Night nor pay the bill for him, Gaku allows her to keep him so Night can collect data on how to become a better lover for use in future models. Whenever there is a problem with Night, Gaku is the one to fix him. Gaku likes sweets, especially ice cream sundaes.