Malygos was bestowed as the guardian of magic by the titan Norgannon. Malygos's kin lived in the northern reaches of kalimdor for the longest of time in the coldest regions.
During the War of the Ancients, Malygos proved to be a key player in convincing the other dragon flights to aid Neltharion the Earthwarder in his quest to throw back the Burning Legion and championed his cause by being the first dragon to bestow part of his essence into the Dragon Soul. When Deathwing the Destroyer betrayed Malygos and the others at the turn of a great conflict, Malygos attempted to erase the item from existance. Having failed to destroy the one item that held complete control over the dragons who had bestowed their essences upon it, Deathwing used the power of the Dragon Soul (aptly dubbed: Demon Soul) to completely obliterate the blue dragon flight. Only a few of Malygos's eggs survived the conflict due to a Red Dragon in the guise of a wizard known as Krasus secreting them away in a pocket demension.
After the Legions of Sargeras were pushed back the Aspects forced the demon soul from Deathwing and used their remaining power to ensure that he could never use it again and hid it in a place where no one could find it save for another dragon.
Thousands of years later (yea.. its a big jump.. during which Malygos pretty much snapped and went insane) Alexstrazsa had been enslaved by the orcs of the Grim Batol. The Demon Soul that had been hidden had once again been found by an orc shaman. The shaman, unable to use the power of the artifact, gave the item to his most trusted warlock, Nekros Skullcrusher (Yes, our server gets its name from the orc who enslaved the red dragonqueen... amusing isn't it?). This warlock learned to use the artifact to control the red dragon flight giving the orcs a presence of power in the skys on the backs of Red Dragons. Krasus (a younger version, don't ask.. I'll explain later), being a consort of his Queen, attempted to rally the aspects to free Alexstrazsa. The epic battle above the Grim Batol was quite amazing with the 3 aspects, Yersa: She of the Dreaming, Malygos: Guardian of Magic, and Norzdomu: Keeper of Time fighting with what power they had left (part of their power was still in the demon's soul) against Deathwing the Destroyer. Deathwing had not given his power to the Demon's Soul and therefor was more powerful than all of them. Their demise would have been inevitable if not for the actions of Rhonin of the Kirin Tor who used one of Deathwing's own scales to split the Demon's Soul in half and freed the trapped powers within. Deathwing was forced to flee and hide. (At this point its sketchy as to what happened to Deathwing but oh well). Malygos still grieved over the loss of his flight for he still belived them to be annhiliated. Nozdormu, who has a body in every instance of time and knows what paths it will take or could take, showed Malygos the pocket dimension that Krasus had stored the eggs in so long ago.
Thats pretty much all I know about the Blue Dragon flight...if anyone wants to add or correct me.. meh!
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"A Warlocks job is to bring pain and suffering to those who annoy him."
- Overlord of the Twisting Nethers, Azune.