Amaterasu had partners, or rather, brothers and sisters. As characters in myths and legends, they didn't exist. It was the people of Xiaori Country who created the three nobles through imagination and faith. Then, Abe Haruki used some unknown method to give wisdom to Amaterasu!
Abe Haruki was not sure about the rest, but it seemed that it was not the chain effect from back then that made both the Yue Ming and Suzhan Ming possess wisdom and appear. This was very likely to happen.
Once Amaterasu devoured Xiaori Country, he might be able to become an invincible rank powerhouse in one fell swoop.
Although he would be restricted by the rules of the dungeon space on the Blue Planet, when he ascended, he would be an invincible powerhouse who could dominate a region.