A Dragonslayer's Peerless Regression - Chapter 28

Protagonist travels between different anime worlds to right wrongs and uncover his reason for being along the way.

After coming out of a tunnel… it was pitch dark.

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.

The Barren Continent, where martial arts are supreme, and strength is honored above all.The once-in-an-era prodigy, Ye Chen, came forth with the ancient and unparalleled divine technique. He cultivated his martial veins, survived the thunder tribulation, merged with the spirit blood of true beings, and shook the six harmonies and the eight desolations with his martial prowess. He roamed the myriad realms and heavens, fighting across the world with the secret realm of billions of stars that were eternal and undying!An endless trove of treasures, worlds of bizarre wonders, sects, ancient clans, fairies, witches, friendships and enmities, and heated battles—all of it was contained therein.