As an Oldwalker Elder Dragon, he was the single most powerful entity in the multiverse. If he chose to step onto a plane in anything but a specific way, he could obliterate it. Worlds lived and died at his whim and will.
Even other Oldwalkers, themselves functionally gods, were children next to him. And above all that, he was a dragon. With a dragon's pride, a dragon's arrogance, and a drgaon's power. And the Elder Dragons were themselves already rivals to Oldwalkers in power. Their war shook Dominia (not Dominaria, Dominia - i.e. the entire multiverse).
Even when the Umezawas managed to kill him, he survived it. He came back to life. Not even death was enough to end him.
And then the Mending lessened him. Began to age him, rendered him, while immensely powerful, mortal.
And he decided FUCK THAT SHIT.
That is his problem.