He's My Fiancée ! : I Went Back To The Past and You ! - Chapter 350 - 351: The Master, Nephew, Disciple-I

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

After transcending to a new world, Ye Xuan miraculously obtained the Swallowing System.

Not only could it swallow everything (wink wink nudge nudge), it could also extract bloodlines, martial arts, godly weapons, medicinal pills, treasures…

“This (beer) is way too strong! Don’t challenge me! Do you believe that I can’t swallow your divine swords?”

- Description from Novelupdates

The world was once at war with 10 alternate worlds. This was known as the Concept War and our world won 60 years ago. All of this was concealed so no normal people are aware of this fact in the current time.

After the death of his grandfather, the high-school student Sayama Mikoto is suddenly summoned by the giant corporation IAI. He learns this world is headed for destruction due to the acceleration of the Minus Concepts. To prevent this, negotiations must be undertaken with the survivors of the other parallel worlds so their 10 concepts can be released.

And so Sayama is caught up in the final battle to clean up after the Concept War which left behind so much enmity.

With a sword in hand and wine in tow, he roams the martial world; her slender waist is light as a feather in his palm.The young man strides forward with a long blade slung over his shoulder and a flask at his side, yet the world of martial arts he seeks remains elusive.As the chaotic world book turns a new page, decades of relentless nights in the martial world pass by.Suddenly, he looks back and finds he has already shattered the mortal realm.