After Thunder Comes Day

Urban high martial arts·devour·single heroine·semi-invincible Seventeen years old, low-level human-level talent, no background, no resources, no teachers. He only has one skill of unknown origin Talent determines the upper limit, but no one said that the upper limit cannot be moved upward on its own. The price is that every time he becomes stronger, his inner demons will grow and become stronger with him. Until the inner demon has fully grown... Will he still be himself?