In the manga, he can play acoustic guitar, and is a fan of singer Matthew Sweet, possibly due to his quirky upbringing (in the original Japanese, it’s The Carpenters).
The author's name, a pen name, was derived from SIG Sauer, a firearm manufacturer, and 'a manga hero', definitely Keiichi Morisato from Oh My Goddess!, according to the afterword in the second volume of Gakuen Kino.
Belldandy was created by Kōsuke Fujishima and features as one of the two principal protagonists in the manga Ah! My Goddess! (ああっ女神さまっ) (along with the character of Keiichi Morisato).