Kaname Isaki
He is a childhood friend with Manaka, Chisaki, and Hikari. He is also the most level headed out of everyone in the group. He seems to be the only one that knows Chisaki has feelings for Hikari.
It is later revealed that Kaname has feelings for Chisaki. Kaname confessed to Chisaki, but she didn’t respond to him and he told her he would wait for her.
After 5 years of the hibernation, Kaname didn’t age.