Unbeknownst to him, Aqua's fraternal twin sister, Ruby Hoshino, is the reincarnation of Sarina Tend?ji, amongst Gorou's people who was a lover of Ai. 4 yrs afterwards, Ai is murdered before the twins by a similar enthusiast who killed Gorou. The lover afterwards commits suicide, but Aqua deduces the murderer can have had his and Ruby's father being