Reincarnated as the Demon King's Son - Chapter 828 - The War Proceed

In regards to the MMORPG Cross Reverie, Sakamoto Takuma boasted an overwhelming strength that was enough for him to be called the Demon King by the other players. One day, he gets summoned to another world with his appearance in the game. There, there are two people that insist “I am the real summon master.” Takuma gets slave-turning magic used for summoned beasts cast on him by the girls –

An unexpected discovery in Machu Picchu has transported a young professional thief from Earth to a world filled with mystical powers and evil plots. With his beloved teacher and best friend killed during the calamity, his only goal is to become stronger, so that he can take revenge for them.This is a novel filled with politics, the struggle for power, evil beauties, and of course, Divine Immortals.

- Description from Novelupdates

He became a teacher at the best magic academy in the empire.
….For being mistaken for someone else.

Chen Yuan transmigrated and became a Mountain Patrol Military Officer.The eight hundred miles of Langdang Mountain is his pasture.Unfortunately, the Great Qian Dynasty is in its final years, with its fate collapsing.Demonic disasters plague the land, bringing devastation to all living beings. The human world becomes a battleground, entering the mortal realm to face calamities.Monstrous beings and malevolent spirits take the stage, disrupting the martial world.Chen Yuan, armed with the Tiger Talisman for Mountain Moving, patrols on behalf of heaven, cutting down mountains and destroying temples.In the eight hundred miles of Langdang Mountain, demons and monsters shall not appear!