The Strongest Guild Master Founded a Nation in a Week - Chapter 21 - Everyone Goes Berserk

As a promise, he went out into the world as an assassin. 3 years later, after becoming the Supreme Assassin, he gave up on everything he had and returned to the ranks of ordinary people. But one day, Kismet, a mystical game created by the National Research and Development had appeared.

Enigmatic hands, spectral frame, and one cunning strike just like the swing of the Grim Reaper. The Supreme Assassin takes on the mystical world, and how his legendary tales sets off, progressively ascending the altar to becoming the best.

- Description from Novelupdates

Reborn in the world of Naruto as the Nine Tails, he finds himself sealed within Uzumaki Kushina. No longer just a mindless beast, he possesses his own will, intelligence, and the power to change the fate of the tailed beasts.Madara : I never thought that my Rinnegan would be crushed by Nine Tails.Hashirama: Times have changed. I once controlled the Nine Tails, and now the Nine Tails controls me.Uchiha Mikoto: Kushina, I didn’t expect you to have something this powerful sealed inside you.Uzumaki Kushina: Each of the Nine Tails' tails gives me a different feeling.At this moment, the Nine Tails stood tall, representing all the tailed beasts.“Tailed beasts will never be slaves!”

I had a supporting role in a modern fantasy.

The loyal dog of a villain with an angel’s name, Cheon Sa-yeon, and an unfortunate supporting character who died on his behalf, Han Yi-gyeol.

In order to escape from Cheon Sa-yeon and survive, he must use the protagonist, Ha Tae-heon.

But Ha Tae-heon, who he thought of as a lifeline, was infinitely indifferent to him. Rather, Cheon Sa-yeon showed interest.

But besides that, something strange happened.

The events that occurred in the original story had advanced, and the gate and monster levels had risen. Even the people were “different” from the original.

The original version I was trying to use was wrong.