Enigma's Breakthrough
And how did he do so? He nurtured a broken son, who became the strongest among the third batch. Strong enough to fight toe to toe with those from the second batch.
And with his son's attainments, he did manage to become stronger, but people doubted whether a realm beyond that realm really existed. And he, himself, never admitted it.
He just claimed to have seen a Breakthrough, but vanished years later. And following his departure, Enigma's father took over the family, becoming one of the strongest beings within their Verse.
It was also the reason why he didn't bare any grudges at all with them. With how fast he was getting strong, he knew his parents were getting even stronger.
Plus, his sister should be stronger than him now, meaning that they were already unstoppable even before he began this journey. His parents should be beyond Ancient Gods by now... or even the Prince of Desolation.