Kotori Monou

Fuuma's younger sister, a delicate child with a congenital heart condition, and a developing yumemi (dreamseer). She was Kamui's very close childhood friend, and despite his initial coldness when he returns to her life, remains steadfastly kind to him. In the TV series, her dream is to become an indigo dyesmith (in the style of Japan's Edo period), well aware of the commitment necessary, and she spends time in her school's library reading up on the subject. (Source: Wikipedia)