Emiko's husband is the shy and thoughtful Kosuke Niwa. He married into the Niwa family and adopted their surname; he is not originally a Niwa male. Kosuke possesses extensive knowledge about magic and has traveled extensively, which kept him away from his son for many years. Upon his return, he gave Daisuke a Rutile that allows him to absorb all the damage received by Dark.
Currently, Kosuke is searching for the secrets between the Hikari and Niwa families. While he can be very serious when necessary, he generally comes across as clumsy, much like his son. He often finds himself embarrassed by his wife Emiko and her antics. Kosuke is one of the characters who joined the series later on, and his original surname remains unknown.
