天川 夏彦

Birthday: June 22, 2014 (Cancer)
Blood Type: O+
Occupation: Rokumei City Private Academy High School Section, Class 1-B
Intelligence: High
Physical Strength: Average
Hobbies: None (hasn't developed any particular long-term interests)
Likes: Calm and peaceful times, his dear friends, Yuuri's smile, hot milk
Dislikes: Thoughtless actions, hurting others, crowds, his old self
Enneagram: Type 7 "The Enthusiast"

Protagonist of √B. A high schooler living in Rokumei City.
A quiet boy who hates standing out in any way. He is by no means emotionless, but he rarely shows any passionate emotions.

He is the one who is there in body, but not in spirit, as he always seems to be gazing somewhere far off.
He tends to simply stick to his daily routine. He is very sensitive and quite perceptive of others' emotions.
He gets very tired of being a part of groups, and is often alone.

His mother (Miyoko) is a renowed scientist who is so busy at work that she rarely comes home. Therefore, Natsuhiko essentially lives alone.

It seems that as a child, he was rather cheerful and mischievious, the opposite of his current self...
He somehow gets trapped in LABO on September 16.