جاک

One of the members in the expedition for Nanakimura village. He seems to have a quiet emotionless personality, but he can easily become aggressive and violent with the slightest prompt.

[Spoiler: His real name is Sasaki.

He used to attend the same school as Maimai. However, a year ago, he was arrested for stabbing a classmate after extreme bullying and way sent to juvy (juvenile detention center).]