I have been thinking about it for 2 days now but i cannot remember much.

There was a protagonist that (i think) is fighting a monster that can move through walls and kidnapped
his/her friends (classmates?)

They are being held inside the ground and the monster gets defeated and the friends gets crushed inside the ground cuz of it.

I think the protagonist awakens some power to defeat the monster also but that can be me misremembering.

I am sorry it's not much to go on...