Jack

Dr. Crane's assistant.
Standing at 190cm, he can seem rather intimidating. But in truth, he's very calm and kind, as well as skilled with his hands. A bit of an airhead, though.
He has no memory of his life before the clinic. He was taken in by Dr. Crane (who was the one that bestowed the name "Jack" to him), and has chosen to work for her to repay her kindness.