Itsuki Takayama

Itsuki Takayama (高山 樹 Takayama Itsuki) is the younger brother of Natsuki Takayama who is in the same year and school as Honoka Sawada and the substitute father of Karin.

Trivia

 * The name Itsuki means "tree" (樹).
 * Itsuki's surname Takayama means "tall, high" (高) (taka) and "mountain, hill" (山) (yama).