Okihara Kotoha

Metis: <Mermaid> (Water)

Childhood friend of Keiji and Manami. They meet again at Suminoe Gakuen after not contacting more than a year. She is very close to the siblings, that when Kotoha moved somewhere else without telling a word, she made Manami very upset. She and Keiji can banter with each other without feeling offended.
Really care about her appearance. Despite the fact that she used to be a tomboy, she is very popular at Suminoe Gakuen and even won a school beauty pagent, gaining her the title "Miss Suminoe". She used to be a swimming club member, but when she awakened her Metis, she resigned.