Do You Want a Human to Be a Demon King?

The jungle in the far north of the world of mortals is a place where monsters and beasts live together. It is called the demon realm. The demon realm stretches over half of the world of mortals. The Demon Realm is called a forbidden land for humans. No one who goes deep into the Demon Realm can get out alive. However, in this forbidden area of ​​​​human beings, there is a boy who punches a giant leopard as big as a small mountain.