Starting With The Sefirah Castle In The Anime World - Chapter 266: Klein

At 18, Alex Kain is whisked away to Eryndor, a game-like realm where he gains 'Skill Synthesis', a talent to fuse skills into godlike powers. Battling monsters and conquering dungeons, he builds a harem of strong women drawn to his might and charm. With the power to return to Earth bearing incredible resources, Alex faces a growing threat that endangers both worlds in this epic of adventure, romance, and ambition.

The leader of the thousand demons, the Demon God Chun YeoWoon. Due to an unfortunate accident, he had been sent to the distant future.

Empires rise and fall on the Yulan Continent. Saints, immortal beings of unimaginable power, battle using spells and swords, leaving swathes of destruction in their wake. Magical beasts rule the mountains, where the brave – or the foolish – go to test their strength. Even the mighty can fall, feasted on by those stronger. The strong live like royalty; the weak strive to survive another day.