Ganta Nakami

Birthday: March 21

Nakami is the President of the astronomy club. As a result of his insomnia, he was perceived as a grumpy and unfriendly person by his classmates.

[Spoiler] Nakami grew up in a single-parent family, with his mother suddenly leaving the family at night while he was sleeping. After this event, Nakami started to feel anxious about sleeping, fearing what dawn could bring upon him and his family. [/Spoiler]

[Spoiler] Soon after learning about Isaki's health condition, Nakami decides that he would become a nurse in the future. [/Spoiler]

(Source: Wikipedia, translated)