コハク

The pretentious speech doesn't match the youthful looks. A person of many mysteries who has a dignified presence. The sword at the waist is 2 shaku 7 sun long (~81 cm). The left eye is constantly closed. Age and gender are unknown. [From Solelo website] It confirms later that Kohaku is female and couple of hundred years old. She had a twin-brother in past. She is the foster daughter of Rouryuu.