MTL - The Earth People are so Fierce (Oh My God! Earthlings are Insane!) - Chapter 48 Click through

Accidentally reborn as the son of the distant cousin of the Squib, the mother of Harry Potter’s friend Ron, and lived in this world as the second generation of Squib for eleven years.

He originally planned to be an accountant like his father in the future, but he didn’t expect fate to play a joke on him, and he didn’t know the slightest bit of magic, but he received the exact same envelope as his sister on his eleventh birthday.

Due to the expectations of his parents, he reluctantly accepted the reality, but inadvertently discovered another secret…

- Description from novelbuddy

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.

Roy died during a war against the Evil God Cult, but somehow, he returned back in time to 30 years in the past where he was just a boy who awaken his summoning magic.

This was the era that belonged to various powerful bloodline warriors, the fervorous era where magic powers and warrior energies were the deciding factor of dominance! With endless ardour and unstoppable courage, a grassroot nobody could also shine and live like a boss!