The Strongest Dragon in the Era of Beast Taming - Chapter 1005 - 999 Time Herald Emperor Dragon

Unhindered in the Demon Domain, the king is solitary!

In the world where immortals and demons strive, a good natured fellow sought the Demon Dao in search of justice.

At the end of his journey, he had eventually become this generation’s Heavenly Demon Emperor.

Although I am not fond of slaughter, I do not dislike it!

Desiring to see the Demon World, this is how I strive, this is how I become the Peerless Demonic Lord!

- 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.

Utsuro no Hako to Zero no Maria, or The Empty Box and The Zeroth Maria, tells the sinister story of Kazuki Hoshino, who is almost madly attached to his everyday life, and his antagonist Aya Otonashi, who suddenly transfers into his class—for the 13,118th time. She majestically announces to “break” him, without paying heed to anyone else around them.

My reunion with her took place in the worst possible way.