Please note: As the events of the Warcraft novels are considered canon according to Blizzard, I will be using those events as a basis for his history. Keep in mind there is an alternate timeline, but that timeline is no longer applicable -- and if you've got a problem with it, blame Chromie and the rest of the Bronze dragonflight.
Who: Malfurion Stormrage, aka Shan'do (honored teacher) Stormrage, aka the baddest druid that ever druid...ed.
What: Night elf – no demonic presence here!
History: Malfurion Stormrage was one half of a set of twins, Illidan Stormrage being his brother. The two had a fairly idyllic childhood along with their close friend Tyrande Whisperwind. As they grew older, the three elves found themselves having to choose their individual paths as adults. While Tyrande joined the priesthood of the Sisters of Elune, Malfurion and Illidan found themselves with a very different sort of teacher -- the demigod Cenarius, who was attempting to teach both of the twins the ways of druidic magic. Druidism was not something that the kal'dorei had previously followed, so the magic that Cenarius was teaching the twins was entirely new to them. Malfurion showed an amazing aptitude for the druidic arts right off the bat, while Illidan, despite being powerful in his own right, couldn't seem to grasp the spells and nuances of nature magic. Cenarius informed Malfurion that his brother was meant to follow a different path (and boy howdy what a path that was), and that it was Malfurion that was destined for the path of the druid, then showing him how to walk the Emerald Dream.
Malfurion had always been a different sort of night elf -- while the kal'dorei that surrounded the Well of Eternity were followers of sorcery and arcane magic, tending towards more flamboyant dress and speech, Malfurion was much more simple and humble. He dressed in a subdued manner, and the magic that he practiced was pretty much the direct opposite of the sorcery of the night elves. He also tended to question the ways and actions of night elf society and of Queen Azshara. These questions left him with few friends and few associates -- but it turns out Stormrage was right to question things, as his first trip into the Emerald Dream was a vision of the Well of Eternity and something terrible going on with the waters surrounding the palace of the Queen.
Turns out Queen Azshara and her followers were tinkering around with the Well – a source of infinite magic power drawn from the Great Dark Beyond (aka the void between worlds, or simply put, outer space). The tinkering, and the sheer amount of power contained in the Well had drawn the attentions of the evil titan Sargeras and his Burning Legion. Sargeras decided it was worth it to corrupt both the Highborne worshippers of the Queen and the Queen herself, promising her a wonderful magical sparkling world in which she could reign for eternity -- so long as she, you know, made a portal strong enough that Sargeras could pop through it, say hello, destroy all life on Azeroth as we know it, and have some tea. This information didn't fly with Malfurion, and so the War of the Ancients began!
The Burning Legion ran rampant through the city of Zin'Azshari and the lands surrounding it, and the night elves fought back as more and more of them realized something was up with the Queen. During the course of these wars, several key events happened: Malfurion grew stronger than ever, using the Emerald Dream to muck around with the portal at the Well. More and more night elves saw his path and his actions and decided they were the right ones to follow, indulging in 'Hooray Malfurion' and 'You sure know what's what' praise and accolades to the twin. Malfurion's popularity was growing in leaps and bounds, largely because he wasn't intent on bringing an army of demons through a portal and destroying the general public.
Illidan grew more angst ridden, annoyed that his brother was getting more attention and praise when clearly he was the superior dude, and took off to join the fighting forces in an attempt to highlight the fact that he was ever so much better than his brother. After receiving a reprimand from a superior officer and being told he was to answer to a human (Rhonin, who we...won't discuss. Time travel. Wibbly wobbly timey wimey things. Keep that in mind.), Illidan had just about had it. The final straw for Illidan came when Tyrande Whisperwind, close friend to both brothers and romantic lead extraordinaire decided, while she was doing priest business and helping out with the war, that she really liked Malfurion. You know, not liked, liked-liked. In that way. Illidan, ticked beyond all reason, went to join Team Azshara in a secret plot to undermine their plans and destroy the Well of Eternity all on his lonesome, convinced that if he could show Tyrande how much of an awesome loner hero he was, she'd decide he was a Really Swell Guy, and ditch his brother.
The war raged, the Legion ran rampant, and the night elves fought back against the pit lord Mannoroth and the eredar Archimonde and won. Malfurion managed to convince his brother that Team Azshara's odds were a really, really long shot to bet on, and that the portal that Azshara and the Highborne had put together needed to be toast. Malfurion and Illidan managed to close the portal -- but not without consequences. The stress surrounding the Well and the portal, not to mention Sargeras' last minute attempt to shove himself through the shrinking portal, caused the whole world to go kaboom. Azeroth itself received a face lift in the form of the Sundering that shattered the once-whole continent of Kalimdor into several different landmasses. Malfurion, Tyrande, Illidan, and everyone else took off for high ground, convening up at Hyjal. Illidan, still annoyed about the hooray Malfurion rabble, decided to make a new Well of Eternity with some vials of water he'd stolen from the original Well, an action that earned him swift arrest. While the night elves wanted to put the twin to death, Malfurion spoke in his defense -- and so Illidan wasn't killed, he was merely locked away for life. Underground. Where nobody would see him or think of him again. Thanks, Malfurion.
Malfurion and the night elves were unsure what to do about this new Well -- they couldn't very well destroy it as the thought of yet another kaboom wasn't exactly appealing at this point. Malfurion went to the dragonflights, who made a tree for the night elves to live in and blessed it with gifts -- thanks to the Bronze dragonflight, the night elves were now immortal, and thanks to the Green dragonflight, they were charged to watch over the new Well and the rest of the world via the Emerald Dream. Malfurion shared a heartfelt and tearful goodbye with Tyrande and headed out to take a nice nap along with a score of new druids, wandering around in the Emerald Dream and making sure everything stayed put.
Tyrande woke him up briefly a few thousand years later due to an attack by the Highborne survivors, who were throwing a hissy about not being able to practice arcane arts anymore. He ordered their exile, earning the enmity of the quel'dorei in the process -- thanks, Malfurion -- said another tearful and heartfelt goodbye to Tyrande, and went back to sleep, spending the majority of the next several thousand years dozing and watching over the Well via the Emerald Dream.
Meanwhile, Tyrande twiddled her thumbs, formed the Sentinels, sighed with longing, and waited for Malfurion to wake up and pay attention to her. This, understandably, made her more than a little cranky -- and then things started blowing up in her face. Orcs showed up, killed Cenarius, there were undead Scourge rampaging through Ashenvale, and to top it all off, Archimonde, the eredar that had been banished to the Twisting Nether way back ten thousand years before, was back. And he was severely annoyed, and wanted the power in the World Tree and the Well beneath it. Tyrande had too much on her hands to handle, and went to wake up Malfurion to ask for his help, letting him know what was going on out in the real world and not the happy go lucky dream world he'd been prancing around in for the past ten thousand years. Malfurion and Tyrande went to wake the other sleeping druids -- the Druids of the Talon, and the Druids of the Claw, on the way fighting furblogs, spiders, and The Largest Panda Ever (Yes, really) in an effort to pull together enough forces to fight back. Tyrande was more than a little short with Malfurion during all of this, reminding Malfurion that she didn't "have the luxury of sleeping through times of great peril."
Ouch, Tyrande. Ouch.