I think that, for the time being, Riboku could even be isolated in his own GOAT tier. I see many folks here that have for example put the likes of Gakuki/Hakuki in the same tier as him but the portrayal of Riboku is just absurd on the whole. Winning a war against him seems like achieving a fucking miracle.
Very few people are close/can truly compete with him to begin with, and even then he still gets some sort of visible edge. He's just that guy.