Chronicles of Forgotten Extra - Chapter 237: A Terrible Sister.

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.

“I beg you, please teach me how to pick up female angels!!!”
Pleaded the twelve-winged angel.

“Teacher!! How can I fool more people into my sect?”
Asked a devil in the devil world.

“Do you know how to save the family cat that died last night?”
Someone in the sky is too embarrassed and asks me quietly.

“All the angel, all the big deity, please I am not God, I am really just a summoner….”
I said painfully.

This is the story of a poor boy and how he becomes the greatest summoner who dominates the six worlds because of an accidental acquisition of Dimension.

- Description from Novelupdates

Being in the World of Arknights...Thing's are going to change drastically and...You best be ready for what's to come ahead.