The Magneto Giant sized seemed a bit light on plot. And it was. But it also brought back a lot of deep cut continuity, and I do not think that was an accident. Magneto says he "collected islands" and that is a veiled reference to, among others, M island. M Island is the weird little base Magneto had in the bermudas back in the day, and it has been referenced several times during the Hickman run. Its most prominent features were the queer buildings, the spiral motives and the huge statues of fish people. In the giant size Namor makes the connection. The spiral is the sigil of the Uhari, the ancient race that once populated Atlantis, and is now living in Antartica (They showed up in Fantastic Four). The three mermaids seem to be uhari as well, and they give Magneto a key. Does it open something in M Island?. Plus this island is also notable because it is the place where Illyana Rasputin was first kidnapped, so there could be some relationship with Limbo. And in an issue of First Class the island was also revealed to have been a prision for an elder god.
IslandM.jpg
So it seems clear to me Hickman is preparing Island M for something. What do you thing that key opens? Do the Uhari have a rol to play in this story? Could this be related to the huge Limbo story Hickman seems to be cooking? To X of Swords even? To the return of Maddie?