How Come I Keep Getting Stronger Even Though I'm Wandering Around in Poverty?

[Supernatural, global myths and legends as well as strange stories, customs, western fantasy, all included, no intelligence] Traveling on a budget in Europe, Zhang Yan stumbles upon a tragic exorcism case. Evil spirits are raging, miracles are looming, what is hidden in the ancient myths? He wanted to break this transcendent journey across civilizations with his own hands!