WARNING: This article contains spoilers for X-Men #8, by Jonathan Hickman, Mahmud Asrar, Sunny Gho, and VC’s Clayton Cowles, on sale now.
Even before Vulcan officially debuted, the Omega-Level mutant’s life was full of mystery. Throughout the '90s, X-Men comics dropped vague teases about Cyclops and Havok having another brother. While characters like Gambit and Adam X was rumored to be a potential Summers brother, a new character, Vulcan, was revealed to be the true third Summers brother in Ed Brubaker and Trevor Hairsine’s X-Men: Deadly Genesis.
That 2006 miniseries established that Vulcan had been part of a previously unmentioned second X-Men team that seemingly perished on a mission in the X-Men's early days. After taking his wrath out on the X-Men, Vulcan turned his attention to the Shi'ar Empire. Through a bloody campaign of conquest, Vulcan took over the interstellar empire, which he engulfed in cosmic conflicts.
However, Vulcan has turned over a new leaf in X-Men's Dawn of X era. As almost all of Marvel's mutants have gathered on the island-nation Krakoa, Vulcan has rejoined his siblings at their family home on the Moon. While it's still not entirely clear how Vulcan went from being a cosmic tyrant to happily grilling steaks with Wolverine, X-Men #8 drops a few major clues about how the third Summers brother finally joined his mutant family.
In X-Men #8, Vulcan has a bad dream after an all-night bender with his old teammates. When Cyclops and Havok wake him up, he tells them that he's had the same bad dream that he's been having every night. In the dream, Gabriel can be seen floating through empty space filled with a psychedelic mix of blues and purples.
While this might seem like a fairly vague setting at first glance, Gabriel's dream almost certainly sees him floating through a rift in the space-time continuum called the Fault, which was also Vulcan's last known location before the Dawn of X era began.
When Vulcan ruled over the Shi'ar Empire, he launched an attack on the alien Kree Empire, which was ruled by Black Bolt, the leader of the Inhumans. Those two powerful leaders took their respective empires to war in 2010's War of Kings crossover. During the final battle between Black Bolt and Vulcan in Andy Lanning, Dan Abnett and Paul Pelletier's War of Kings #6, the two created the Fault and seemingly wiped each other out of existence when they both unleashed their powers near a detonating Terrigen Bomb.
Although both leaders seemingly perished in the explosion, Black Bolt reappeared in 2011's FF #6, by Jonathan Hickman and Greg Tocchini. In a sequence that's identical to the beginning of Vulcan's dream, Black Bolt wakes up inside the Fault. Then, the Inhumans leader takes on a giant, Lovecraftian alien being transported back into the regular Marvel Universe.
Although Black Bolt found a way through the supposed unescapable Fault is supposedly unescapable after a year, Vulcan seemingly perished there, since he wasn't seen for the next decade. And when Gabriel reappeared on Krakoa, his return and friendlier disposition could be easily explained by the X-Men's resurrection protocols.
However, X-Men #8 firmly establishes how that wasn't the case. As a data page in this issue explicitly points out, Vulcan never really died, and he has the memories of the Fault to prove it. While Vulcan is powerful enough to have handled almost any creatures that might've attacked him in the Fault, it's not clear if he escaped or was rescued from that hole in time and space.
Regardless of how Vulcan got out of the Fault, the fact that he did dramatically reframes his current place in the X-Men's world. The Vulcan who cooks out with the X-Men today appears to be the exact same character who once led empires to war. While plenty of former villains have joined the X-Men over the years, Vulcan went through one of the biggest personality shifts in Marvel history, and he may have done it naturally. Although there's no guarantee that Charles Xavier or another telepath didn't manipulate Vulcan's mind, the X-Man appears to have chosen a new, less tyrannical path for himself.
With Earth and potentially the Shi'ar Empire set to go to war with the combined Kree/Skrull Empire in Marvel's upcoming Empyre crossover, Vulcan is almost certain to play a major role in the coming months. While upcoming issues of X-Men may reveal more details about how Vulcan returned from the Fault in Marvel's stars, this former tyrant may very well get the chance to show the X-Men and Marvel's collective cosmic empires just how much he's really changed.