I recently read a manga which involved a boy entering a new school and on the way he meets a girl with a wooden sword (I think) and befriends her.
When they enter the school they are instructed to write a word which they want to be or so. The boy writes the word 'change' I think. After that, the word gets inscribed on them (on one of their body part like hand) and they could use that power.
Before long, the school is raided by monsters and their teacher tells them to fight them in order to survive. The girl fights with her transformed sword I think, and the boy initially transforms into a stuffed doll and when the girl was in danger of getting killed he transforms into a boy with different looks, takes her sword and kills the monsters.
I wanted to know the name of this manga. Thanks in advance.