The three Sanctums were the three nodes suppressing the rift, supporting one another to envelop the entire Earth.
Ancient One's primary concern was dimensional invasions. Other matters would not draw her attention unless they reached a certain level. Even during the Chitauri invasion, she had not cared much, so long as the New York Sanctum remained safe.
And Dormammu was a terrifying existence capable of destroying the world.
Devouring Earth would merely turn it into part of his nourishment, something extremely similar to Xu Yue devouring the World Will. Setting aside the methods involved, in terms of sheer scale, he was theoretically no weaker than Xu Yue was now!
Kaecilius had been having a truly miserable time lately.
Something had gone wrong back then. Ancient One had somehow learned of what he was doing before he was exposed, then began hunting him down.
Only because he was skilled enough had he managed to evade her suppression.
He had spent all that time living a miserable life on the run.
Only recently had he finally found an opportunity and received Dormammu's power!
The Dark Power pouring through the world's barrier—the powerful, irresistible force—had deeply intoxicated Kaecilius.
This was the feeling!
The reason Ancient One was so powerful, and had lived for so long, was because she too had drawn upon the power of the Dark Dimension.
That was why the image he had held of her had shattered, giving rise to thoughts he should never have had.
If she could use it, why couldn't he?
With his talent and ability, once he began using this power as well, even Ancient One would no longer be his match!
And unlike Ancient One, who could only personally draw power from the dark world, after pledging himself to Dormammu, he could actively receive His