Doryoku Shisugita Sekai Saikyou no Butouka wa, Mahou Sekai wo Yoyuu de Ikinuku.

A boy named Ash, who was a martial artist in his past life, is reborn in a world where magic is part of everyday life. After discovering he cannot use magic, his parents leave him in the forest at age five. A former hero takes him in, and Ash trains hard daily, longing for magic as he did before. By age sixteen, he still cannot use magic, though he doesn't realize he is already strong enough to defeat a demon lord with one punch. The story includes eight additional chapters.