Long ago, the Shadow Demon King, the greatest enemy of this world, was defeated by two heroic boys: Fian, who possessed infinite battle aura, and Nevia, who wielded infinite magical power.

Since then, Fian and Nevia continued to live peaceful lives.

However, this world... [Planet Nean] was sustained by a finite energy known as the Dark Orb, which maintained its planetary form.

Being finite, this energy gradually depleted, and the planet was heading towards collapse.

Before the planet could completely collapse, the two, known as heroes,

integrated with the Dark Orb to eternally infuse it with the infinite magical power and battle aura hidden within themselves.

Thus, the Orb regained its brilliance, and the planet's collapse was averted...

Once integrated, they could no longer act on their own. But the two harbored a persistent anxiety they couldn't shake.

Approximately 1000 years later...

Suddenly, Nean—a young man who manifests when Fian and Nevia merge into one—awoke in a forest.

Immediately after his revival, Nean was bewildered by the suddenness of it all, but he gradually recalled the heroes' conversation.

The persistent anxiety... and how they had made preparations for Nean to revive when the planet faced a looming crisis...

「“Does my revival mean... that the world is facing another crisis...?”」

Nean stood up, and accompanied by two elf girls he meets on his journey, he once again travels across this planet... [Planet Nean].

・・・

Nean, who 1000 years ago, as a hero, defeated the Shadow Demon King. As a mentor to the two girls, he travels, teaches magic, and sometimes finds himself learning from them in return...

Amidst these varied experiences, he investigates the reason for his own revival—the nature of the looming crisis—and eventually uncovers the truth.

※This work is a story set over 1000 years after the world of the previous work, "When I Reincarnated in Another World, I Became Two People. (https://ncode.syosetu.com/n4720eg/)," but it can be enjoyed even without having read the previous one!