Three world beheading ghost dragon 1: human world

A teenager who just graduated from high school, because of a strange dream, entered a world like RPG role-playing games. In this world full of sword and magic, he became a rookie mercenary with great potential. With the entrustment, he became more and more familiar with the world. At the same time, the mysterious veil of the ghost world and the Dragon world was gradually lifted, and everyone began to be involved in a war across the three worlds.