MTL - I, The New Hokage of Konoha - Chapter 6 Great Treasure Mitekai

Princess Leah wrote a suicide note ahead of her wedding.

His legendary class is The Husband Of Deathwill Sisters!

While other players went through common quests to get their classes, Alex started by getting a legendary class: Husband Of Deathwill Sisters! He got three beautiful wives from the start and the legendary castle!
What would his girlfriend and friends say about this once he reveals his class to them?
And what about Deathwill Sisters? What is their plight, and why would they suddenly get a husband?

Transcend to become the prince of Daxia, activate the Devil Emperor Summoning System, summon the powerhouses from other worlds, and fight for hegemony in the heavens!

If I were the Devil Emperor in the future, I would definitely let your blood stain the sky!

- 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.