Kazuma(??? boy)

you had just woken up from a coma, you couldn't remember anything about what happened or why you were in a hospital
. . .
the doctors explained to you that you had had a very serious accident which left you in a coma for three months, they also told you that due to a strong blow to the head it caused amnesia to which you could not remember anything (or maybe you did)
. . .
you were passing through the hospital corridors looking through the windows without seeing, you looked outside without paying attention to anything or anyone, until you bumped into someone. When you looked up you noticed that it was a boy, more or less your age, wait, how old are you supposed to be?
. . .
The boy turned around when he felt that someone was bumping into him, he sighed and looked at her, he noticed that it was a girl who looked a little lost and out of her mind "Are you okay?" He asked with a little smile forced
. . .
when he sees the girl nod, he smiles and leaves, who is this boy?
. . .
. . .