Reincarnation in Another World: I Used Magic to Kill People Crazy

The boy who cultivates immortality on earth traveled to the magical world! The princes and nobles are corrupt! The brave men of the earth are arrogant and extravagant! The situation is unstable and war breaks out! The devil has resurrected and the end is coming! Let's watch the young man prove his enlightenment and become an immortal, killing his way through other worlds!