Although Aesces is increasingly letting things slide—ah, no, letting go—but in summary, suffice it to say, the Undead Tribe's goals have basically been accomplished.
The same goes for Triton.
Even though Hill never asked Aesces what Triton has conceded, from the chain of islands ranging from small to large, suddenly rising from the seabed, crisscrossing the ocean and between continents, one can see that this Sea Messenger did indeed do something.
Previously, there weren't so many islands on the ocean.
Triton's ability to control the ocean is indeed not weak, but islands, after all, are connected to the land, and the more they are, the easier it is for Aesces' power to invade.
Therefore, don't think that just because the world has turned into a desert due to Triton's invasion, that Aesces' abilities are weak.
He just has a somewhat stubborn head and is prone to tunnel vision; perhaps this is a common problem of an Earth Deity purely transformed by the Earth System Law.
