Adam X (the X-treme) is a comic book character created by Fabian Niceza. Debuting in X-Force Annual #2 back in 1993, Adam X (the X-treme) is a mutant with the power to make anyone’s blood literally boil after he cuts them (or, really, once the blood becomes oxygenated). Adam X (the X-treme) refers to this as “flashing”, for some reason. He was set up to have major role in the X-Men universe, with hints being dropped that he was the third Summers brother (after Scott/Cyclops and Alex/Havok).
Then, Marvel kinda stopped caring. Adam X (the X-Treme) would show up every now and then, but his plot line never really went anywhere, and the third Summers brother turned out to be some dude called Vulcan. Eventually he became a walking punch line mocking the tryhard edginess of ’90s super hero comics. The last we saw Adam X (the X-treme) continuity-wise, he was a prisoner in the Mojoverse.
Then, in the year of Our Lord Two Thousand and Twenty One, Fabian Niceza penned X-Men Legends #2, where it was revealed, via flashback that Adam X (the X-Treme) was a Summers (half) brother, being genetically engineered from the DNA of Katherine Summers and Shi’Ar warriors.
Unfortunately, to preserve the continuity, the Summers boys had their memories erased, but I’ll still count this as W for ol’ Adam X (the X-Treme).
Stay X-Treme, folks!