The main heroine of Tales of Hearts, and Hisui Hearts's younger sister. Kohaku is a kind girl but also a trained martial artist, and won't hesitate to use her skills to end squabbles between Hisui and Shing. Kohaku and Shing each gain a crush on each other, which irritates Hisui to no end.
She makes her first English appearance as a cameo boss character in Tales of Graces ƒ, where her name is translated to Amber.
