Not much is known about Jun's personality.
Jun's appearance is never shown.
Chapter Three: No One Lives Forever
Akiko Kusatsu asks Masami out on a double date, along with Sachiko Noguchi and Jun Sakamoto. He accepts the proposal. Later, the group meets at the station, running into Keiji Takeda, who is waiting for his girlfriend, Touka Miyashita, who was seemingly running late. After the movie, the group notices 'Minako Yurihara' walking on the street.
After leaving the karaoke place, Sakamoto offers to take Noguchi home, leaving Masami to escort Akiko, who begins to feel sick all of a sudden. Noguchi is hesitant to be left alone with Sakamoto at first, but is eventually convinced (although the two would end up having intercourse that night, leading to Noguchi's old fashioned father tracking Sakamoto down and cursing him out in front of his entire class).
- Jun's last name, Sakamoto, means "tree on a slope".
- Jun's first name means "cleanse".