Nayuta Tenkawa

Nayuta Tenkawa (天川 なゆた, Tenkawa Nayuta) is a mysterious girl being cared for by Mihari Oyama's faculty advisor Chitose Azuma. A loner with an unknown background and no social life who wishes to be Chitose's research assistant, she is enrolled by Chitose at the same middle school as Mahiro Oyama during Mahiro's second year in order to monitor Mihari's experiment without her knowledge. She befriends Mahiro after revealing that she knows the truth about her, and quickly joins Mahiro's group of friends.

Etymology

 * The name Nayuta is a Buddhist term referencing a very large number, over 100 million.
 * The name Tenkawa means "heaven" (天) (ten) and "river" (川) (kawa).

Manga

 * Mahiro's Big Secret (Part 1)
 * Mahiro's Big Secret (Part 2)