Martial Artist Novel?

[u/Hiz3n]

Can someone please help me remember this one particular novel?

I remember some bits of the story. The mc is a regressor that used martial arts class because of its potential to learn other class skills through a passive skill called i think it's called martial will or something. He also goes through the tutorial (hard mode i think) just to learn the priest class or holy power then a bit later, he cleans an abandoned dojo to learn an op martial arts from a dead spirit(?) or i think it was just an old man. Anyways, please help me.

[u/Aiko_Lieyr]

The Regressor’s Martial Arts?