Wakisaka (脇坂, Wakisaka) was a social studies teacher at Fujimi High School.
Little is known about Wakisaka other than that he teaches social studies at Fujimi High School.
It is unknown how he looked like before becoming one of "Them". As one of "them," he has the typical features which include grayish skin and white eyes. He has black hair and wears a red vest over a white shirt, sweatpants, sandals, and a wedding ring (implying/indicating he was married).
Nothing is known about Wakisaka's history.
Nothing is known about Wakisaka's personality.
When Takashi, Rei, and Hisashi are attempting to escape from the school through the administration offices, they encounter Wakisaka, who has become one of "them." They try to avoid him, but he starts moving towards Rei. She stabs him through the heart with her broom handle, but he is unaffected and continues to advance on her until she is on the ground and backed into a wall. She is unable to pull her broom handle out of his chest, so Hisashi grabs him from behind, and she pulls it out. Just as Hisashi thinks he has him under control, Wakisaka overpowers him and turns around to bite Hisashi on the arm. Hisashi tries to pull him away, but Wakisaka will not release his arm, even when Takashi hits him and Rei stabs him. When Rei tells Takashi to do something, he realizes he has to hit him in the head to kill him. He smashes his head with the baseball bat, and Wakisaka dies. Wakisaka's body was seen one last time when Saya and Kohta run past it as they attempt to make an escape.
- In Yen Press' English version of the manga, Rei calls Wakisaka a grammar teacher, while in the anime version he is stated as Social Studies teacher.
- He is the first one of "them" to be seen killed.