This series fully on the "that wasn't even my final form" trope train.
Which, not unfitting, given its premise. But I do wonder where the ceiling rests, if there is one at all. At some point they're going to be god-killers if they haven't erased a deity already by now, and Cross is essentially set up to surpass his Masters Three.
Akira Toriyama would be proud.
Thanks for the TL