“The Saviour Of This World” is a term that refers to 5 different Naruto Characters throughout the series. Even though there was but one Saviour, all 5 of these Characters were called the saviour at one point or the other.
Here are all 5 Naruto Characters who were called the Saviour.
5. Hagoromo Ōtsutsuki
Hagoromo Ōtsutsuki is better known as the Sage of Six Paths. He was the one who, along with his brother, defeated the Ten Tails and Kaguya Ōtsutsuki. Even since then, it was prophesized that whenever a calamity strikes, someone with a Rinnegan will come forth and save the world, once again, just like Hagoromo Ōtsutsuki did.