Quantum

In a world where humanity has gained magic to fight against the Six Dragons that threaten to destroy the world, Yakatani Agito, despite the lack of mana in his body, has mastered swordsmanship and became known as the Sword Saint. In exchange for his death, he saves his own world from the threat of the Six Dragons, but their goal was to awaken an even more terrifying dragon 100 years after. The world would be destroyed if things continue this way. Agito, who was supposed to be dead, wakes up 100 years in the future due to reincarnation. This time, in order to save the world, he takes his sword and rises up once again.

For the Hero, Leo Demonhart, saving the world isn’t all it’s cracked up to be. After he vanquishes Demon Queen Echidna, the “grateful” people would rather give him the stink eye than show any respect. Now he’s come to Echidna’s castle with résumé in hand, but his old foe isn’t exactly fond of the guy who trounced her forces. It’s up to Leo to use every trick he knows and get in her good (evil?) graces—a cushy gig as a minion of darkness is on the line!Source: Yen Press, Vol. 1Original Web Novel (Raw) Alt. Official English: Yen Press