WARNING: The following contains spoilers for Giant-Size X-Men: Magneto by Jonathan Hickman, Ramón K Pérez, David Curiel, and VC's Clayton Cowles, on sale now.
Magneto has been many things over the years, ranging from the most dangerous foe of the X-Men to one of their most powerful members. He's also proven to have one of the most bizarre histories in the Marvel Universe, and his most recent appearance follows up on a weirdly specific aspect of the character's history.
In Giant-Size X-Men: Magneto, the Master of Magnetism has just helped take control of an island, which has been a surprisingly consistent aspect of the character over the years. As he even admits in this issue, he has a habit of collecting islands, and he's taken over entire islands across the world multiple times. Now, we're taking a closer look at Magneto's odd collection of islands in the main Marvel Universe.
EMMA'S ISLAND
In Giant-Size X-Men: Magneto, Emma Frost approaches Magneto about a new idea she has concerning an additional island base for her Hellfire Organization. As a favor to the White Queen, Magneto agrees to help claim the island and develop it for mutant use. Heading to the Faroe Islands (roughly two hundred miles north of Scotland), Magneto ends up helping the owner of one of the island -- the former X-Men ally Namor -- investigate the disappearance of Atlantean explorers that happened in the waters surrounding them.
In exchange for saving his life and defeating some sea-witches, the Sub-Mariner allows Magneto to take control of the island for Emma. Using a shipping vessel full of metal he'd brought along (including the wrecked remnants of a Sentinel), Magneto is able to quickly construct a massive tower for Emma to serve as a secondary base of operations. It's implied that only a handful of people will receive "invitations" to the island, but Magneto certainly seems to be a part of that collective.
ISLAND M
Located in the middle of the Bermuda Triangle, this ancient island was once connected to terrible beings such as Shuma-Gorath in long-forgotten times. This mystical quality remained even after it sunk to the bottom of the sea. The island was found by Magneto in the middle of the Atlantic Ocean and quickly became a hidden base for the Master of Magnetism, with Magneto using his powers to raise it once again above the water.
Under Magneto's care, the island, which first appeared in Stan Lee and Jack Kirby's X-Men #4, was intended to make a sanctuary for mutants on the island, although it wasn't meant to be following a battle with the Avengers. The Brotherhood was briefly based there, and the X-Men themselves would later use the island as a temporary base of operations. This continued even when Magneto was a leader for the New Mutants, who brought the group of young mutants to the island. The island is also the site of the portal to Limbo that led to Illyana being trapped in the demonic dimension for seven years and growing older to become Magik.
GENOSHA
Located off the coast of Southeastern Africa, Genosha was initially a seemingly prosperous nation that secretly used slave labor of various mutant citizens to earn pedigree. After it debuted in Chris Claremont and Rick Leonardi's Uncanny X-Men #235, this truth was eventually exposed to the world, and the government was overthrown by the X-Men and their allies in the "X-Tinction Agenda" crossover event. Following that conflict, various conflicts engulfed the island, until the island nation was ceded to Magneto by the United Nations and he was able to install a sense of order.
It quickly became a sanctuary for millions of mutants from across the world, until the day Cassandra Nova's Wild Sentinels were unleashed on the nation and wiped out nearly all of the 16 million residents on the island in Grant Morrison and Frank Quitely's New X-Men #114. The ruins of Genosha have been a consistently dark location for the heroes of the Marvel Universe to return to, being the site of major conflicts during House of M, Necrosha and AXIS. However, many of the 16 million dead might soon get another chance at life thanks to the resurrection protocols the X-Men have devised.
KRAKOA
While Magneto might not be the only one to lay claim to Krakoa as a home, he's certainly seen as one of the founders and leaders of the island. Once part of an ancient land from millennia ago, the living island of Krakoa became a constant element in the lives of the X-Men after it briefly captured almost all of the team in Len Wein and Dave Cockrum's seminal Giant-Size X-Men #1. It took the formation of an entirely new team of X-Men to save them -- with one team of unknown X-Men even perishing against Krakoa, as revealed by Ed Brubaker and Trevor Hairsine's X-Men: Deadly Genesis -- and seemingly destroyed Krakoa by throwing it into space.
Krakoa eventually resurfaced on the Earth and even became a part of the X-Men's base of operations when Wolverine opened the Jean Grey School, before becoming a new island nation thanks to Charles Xavier, Magneto and Moira McTaggert. Magneto sits amongst the Quiet Council, the ruling government for the nation, and has quickly established himself as a crucial part of the island's leadership.