Vulkan
Vulkan is the Primarch of the Salamanders. He is notable for being the only black man in the galaxy, as well as a fuckawesome Smith, advancing a civilization to the Steel Age in a matter of months, as well as being perhaps one of the only likable Primarchs. He does not pity the Dark Eldar fools who raided his planet.
Like all Primarchs, he was dropped on a far-flung planet as an infant, and worked his way to a position of power. Some Primarchs became powerful by being good at politics and bureaucracy, or by kicking enemy ass. Vulkan did it by being really fucking smart and murdering as many Dark Eldar as he could find with massive hammers, both of which are fine occupations for a Demigod. He also made some really cool stuff, which the Salamanders have been spending all of their free time trying to find.
He is also a perpetual, which means that he regenerates for ANY injury, even the ones that actually kill him. With enough time, he can return from a death which vaporized him to atoms, find the culprit, and kick his sorry ass to one edge of the galaxy to the other. Konrad Curze realized this the hard way. He inherited this ability from his father, which implies that the Emperor is a perpetual as well. This can provoke long and passionate debate.
Notably not the awesome gun, but still a pretty cool guy.
How It All Began
The Primarch of the Salamanders legion was Vulkan. Rather than be dumped in a volcano for being a bad omen, as is the fate of many small children who crash on feudal death worlds in space pods, Vulkan grew up the adopted son of a blacksmith, from whom he learned the basics of metallurgy. Of course, being a genetically engineered super-soldier like his brothers he reached adulthood at the age of three and started inventing new alloys like they were going out of style, bringing most of the planet up to the late Steel Age in a matter of months.
Anyway, Vulkan lived out his life more or less as normal for a super-strong genius blacksmith, until the Dark Eldar came to town. Nocturne, it turns out, was a favorite raiding destination for a group of Dark Eldar pirates. The populace, who had advanced to about the iron age before Vulkan came along, generally tended to hide from the space rapists with guns that shoot poisonous glass, but Vulkan didn't share their good sense (possibly having something to do with the fact that he could have tanked multiple RPG-7 rounds to the torso and only gotten mildly pissed off, but whatever). Instead, the first time they came, he grabbed a pair of blacksmith's hammers and went to town on the aliens. He eventually won, driving them off the world never to return, and if this sounds suspiciously familiar then congratulations, you're paying attention. If you also noticed that Vulkan predates that character, making the other one the rip-off, then even better! We will make an expert of you yet!
Shortly after Valt-- I mean Vulkan drove off the raiders, his settlement threw a bigass competition to see who had the biggest man-parts. Amongst the events were to be anvil-lifting, weapon-forging, and bigass fire-breathing dragon-thing slaying. Or something like that. A stranger ended up intruding on the ceremony, and proved himself Vulkan's equal in every contest except the salamander slaying, which Vulkan won by virtue of his own thick-headedness and the stranger saving his sorry ass. Vulkan pledged his loyalty to the stranger immediately after being declared the victor (what an ass), and with insufferable predictability the stranger revealed himself to be the Emprah.
The rest, as they say, is history.
Fate
While the rest may be history, what happened after the Horus Heresy is an absolute records nightmare. During the Drop Site Massacre, the Salamanders took such severe losses that they were reduced to 780 battle-brothers. But the worst part of the Horus Heresy was the fact that Vulkan disappeared (when it happened is somewhat in flux; older fluff states that it happened some time after the adoption of the Codex Astartes (which Vulkan refused to support), but the new Horus Heresy novels indicate that it happened at the Drop Site Massacre), with no trace of him besides a book listing a set of nine artifacts he had left behind. In response, the Salamanders created the position of Forgefather, chosen from a Company Captain who would travel the galaxy searching for information on the fate of Vulkan and his nine Artefacts of Vulkan. So far, five have been discovered, three of which are pieces of wargear used by the Forgefather. Another is a massive laser weapon used to shoot out incoming ships trying to attack Nocturne. The fifth is a downed forgeship used to create wargear for the Chapter, which, alongside their unique practices, is the reason they have so many master-crafted weapons. The locations--and even the form--of the other Artefacts are completely unknown. The Salamanders hold that once all nine Artefacts have been located, Vulkan will return to the Salamanders and lead them once more.
Like Leman Russ, but with more style.
Also, the Horus Heresy novel Vulkan Lives has finally put an end to this debate by confirming that Vulkan is DEAD...maybe. The afterword bizarrely mentions that "someone else can take up the mantle of what happens", and other parts of the book imply that Vulkan might even be a Perpetual like John Grammaticus, Ollianus Pius, and the Emperor (which is heavily implied). Konrad Curze also tells Vulkan that he killed him dozens of times, only for him to just keep coming back to life. It's all rather confusing, to say the least.
Although, perhaps it is similar to the Sanguinor of the Blood Angels. The Sanguinor being a Blood Angel who literally transforms into Sanguinius himself when the Chapter (or, I suppose, Legion) needs him most. This has, in fact, happened before and with predictably devastation effect on the enemy. Unfortunately it is currently temporary. Perhaps if the Legion overcomes its blood thirst... anyway, it is possible that once all the artifacts are recovered, that the "Forgefather" might become a new Vulkan in the same way as the Sanguinor, but permanent. This possibly extends to all the other chapters as well in some way.
The whole "Perpetual" thing doesn't help clarify things, either. Given that Vulkan can survive the worst deaths, making planetfall barely naked and burning to ashes in the process, the question arises if he DID survive that. If he did, he landed on Macragge and despite being jerks, the Smurfs will care for him until he fully recovers, a scenario which Vulkan trusts will happen.
In other words, it didn't really put an end to the debate at all. Nerts.
The 6th edition codex more or less confirmed Vulkan was still alive after the Horus Heresy as he talked to Roboute Guilliman about his issues with the Codex (namely the fact that the Salamanders didn't have all that many marines left to fill one chapter left alone two).
Scratch all that, thanks to Dan Abnett, we know Vulkan is dead, stabbed by a Fulgurite Spear wielded by John Grammaticus and buried in 'The Unbound Flame', which turns out to be a casket holding his dead body. But given BL's current track record so far, they'll probably retcon it AGAIN to say that he's not entirely dead and that all his relics can revive him or something. Honestly, it's as likely as anything else by now.
| The Primarchs of the Space Marine Legions |
|---|
 Loyalist Corvus Corax - Ferrus Manus - Jaghatai Khan Leman Russ - Lion El'Jonson - Roboute Guilliman Rogal Dorn - Sanguinius - Vulkan |
 Traitor Alpharius/Omegon - Angron - Fulgrim Horus - Konrad Curze/Night Haunter - Lorgar Magnus the Red - Mortarion - Perturabo |