Hmm, hello, I was wondering if you could help me find a certain manga I don't remember much about.

This is what I remember:
. male mc
. something about having created the universe again from scratch after destroying it, or living in a delusional world he himself created after tragedy
. Said tragedy had something to do with a girl he was close to (sister? friend? quasi-lover?) disappearing (perhaps dying?)
. He has a weird power (which allowed him to create that illusion/universe I was talking about)
. there's a girl who shatters that illusion with her own power (I think) and takes him with her to a magic boarding school (or something like that)

he meets more girls, stuff happens, his power is very very powerful and pretty unusual

and that's all I remember

anyway, thanks ^^

that's it, thank you!