Perfectly identical, the only way you can tell them apart is that Kin wears mostly black, and Gin wears mostly white... you know, unless they want to mess with you and they change clothes. They both live in Wayward City (born and raised), so they have had very messed up lives, making them into incredibly bad people. However, their love for each other is immeasurable and difficult for some to understand. They are both sado-masochists, though Gin has more scars because Kin is the dominant.