Kyou no Cerberus

Kyou no Cerberus, also known as Today's Cerberus, is a manga by Ato Sakurai serialize in Monthly Shōnen Gangan. The series ran from January 22, 2014 until May 11, 2018.

Chiaki Mikado was bitten as a child by a mythical creature known as Cerberus which caused him to lose a piece of his soul. Eight years later he finds little joy in life, and is surprised one day when the Cerberus returns offering to help. Chiaki soon discovers that the creature is made up of three very different personalities that share the same body. Kuro really wants to make him happy, Shirogane shows a tsundere side, and Roze is quiet and possibly in love with him. As the story progresses Chiaki learns more about the three who want to help him.

Rir Rir (Chapter 9)
Looking for a new snack, the Norse wolf Fenrir sets her sights on Chiaki. Later, Chiaki and Hinata enter their class to find everyone entranced with the new transfer students, "Rir Rir". She then proceeds to hypnotise both of them as well. When Shirogane attemps to help them, Fenrir gets the students to fight her. Shirogane is forced to escape with Chiaki after freeing him from his trance. She soon returns with back up and frees the rest of the students. After being defeated, Fenrir is taken away by her sisters to be punished.