Who is the protagonist? Is he an upgraded fighter who works hard and keeps getting stronger? Is he the aura of the protagonist who can't be beaten no matter how hard he fights? Is he the king of pick-ups (or pick-ups) who has three thousand beauties in his harem that everyone loves?
No!
He comes out with a max-level account and all kinds of awesome equipment, such as the Blood Succession Snare, the Nine Magatama Reincarnation Eye, the Devil Fruit, the telekinesis ability, and the domineering power. As for the protagonist, he is actually just a dou bi.
The worlds that will be tentatively mentioned are Naruto, Pirates, Hunters and Gintama, and we will talk about the others.
After thinking about it for a long time, I changed it to pure love, yes.
The protagonists are all time-travelers and have more or less knowledge of the original story.
The protagonist of the first world (Naruto) is the third son of Otsutsuki Kaguya (not Zetsu, the protagonist is an original character), the younger brother of Hagoromo and Hamura. He has the Nine Magatama Samsara Eye, Byakugan and Blood Successor Snare. It is almost based on the ability setting of Otsutsuki Kaguya, but... It's a joke.
After carefully thinking about the setting, I deleted the originally set Gintama first, because... I really can't imagine a situation where Teacher Songyang or Kyon are funny. Forgive my poor imagination, let's do this for the time being.