Eiden is the main character of the game Nu: Carnival, voiced by Netoru Irakusa.
Official description from the game’s website:

A product designer for a sex toy company, Eiden grew up in an orphanage where he developed a strong, independent personality. He first realized he was gay during puberty and has since had several on-off relationships. He enjoys playing the role of both bottom and top and when it comes to sex, he's very open-minded, with a long list of fantasies and desires.