Arugal

Archmage Arugal is a former mage of Dalaran who lived within the ruins of Shadowfang Keep and was later raised from the dead. He is most notorious for having unleashed the worgen once more unto the world by freeing them from the Emerald Dream.

The Third War
Originally a respected patriot of Gilneas and a royal archmage, Arugal eventually became a member of the Kirin Tor of Dalaran. He used to stay at Valgan's Field in northern Silverpine Forest. Dalar Dawnweaver—a Kirin Tor mage later raised as a Forsaken—considers Arugal to have been a charlatan whose knowledge of spellcasting was so transparent that he was unworthy to even clean chamber pots in Dalaran. Indeed, Arugal used enchanted items to reinforce his weak magic.

After the Scourge destroyed Dalaran and most of its populace, Arugal returned to his homeland of Gilneas. When the Scourge reached the Greymane Wall protecting Gilneas' northern border, Arugal was called by King Genn Greymane to help him find a way to protect his kingdom. Arugal told him about the worgen, a mysterious race he had learned about, which could be summoned to help them. He warned Genn about the worgen's strength and ferocity, but the king decided to enlist their help. Using Ur's research, Arugal summoned worgen to attack the undead that attempted to pass the wall. Though they were successful in killing the Scourge, they later turned their rage against the Gilnean soldiers, turning some of them into worgen. This started spreading the worgen curse all through Gilneas.

Some worgen later sieged the keep of the noble Baron Silverlaine above the small hamlet of Pyrewood Village, causing the keep to quickly fall into shadow and ruin. Driven mad with guilt, Arugal adopted the worgen as his children and retreated to the keep he named Shadowfang Keep. He resided there serving the worgen leader Alpha Prime, protected by his massive pet Fenrus and haunted by the vengeful ghost of Baron Silverlaine.

World of Warcraft
Eventually, Arugal started his own worgen cult by spreading the worgen curse to places like the Deep Elem Mine and Pyrewood and using his magic to keep the worgen under his control. Soon, he had worgen packs such as the Shadowfang pack and the Moonrage pack to do his bidding.

The Kirin Tor sent Sorcerer Ashcrombe to Shadowfang Keep to check Arugal's progress against the undead, ignorant to the fact that the archmage had now been driven mad. His activities eventually drew the ire of the Forsaken and he was later assassinated by Horde adventurers.

Wrath of the Lich King
After he was defeated and beheaded by agents of the Horde, Arugal's headless body was buried at the foot of the path leading up to his former stronghold of Shadowfang Keep. The Lich King saw fit to bring him back as one of his puppets, so the San'layn princes Keleseth, Valanar, Theraldis and Atherann resurrected Arugal as a ghost in the service of the Scourge and sent him to the Grizzly Hills to subvert the trapper communities.

As indicated by Theraldis' comments, Arugal was sent to Solstice Village to convert the population into worgen, and later did the same in Silverbrook. He then settled his base of operations in Shadowfang Tower on Bloodmoon Isle, off the Eastwind Shore. The majority of the populations of the trapper villages willingly joined the Wolfcult, while those who resisted were killed or (in the case of the workers of the Hollowstone Mine) cursed to undeath.

He seems to command the Bloodmoon pack of worgs. He has three lieutenants: Varlam (a human cultist atop a worg), Selas (a worgen), and Goremaw (a worg).

Arugal, along with his three lieutenants, was eventually put to a true end.

Cataclysm
Arugal has been replaced by Lord Godfrey as the final boss of Shadowfang Keep. However, Arugal's legacy remains, as worgen death knights are said to be former servants of Arugal who escaped from Shadowfang and later became minions of the Lich King.

Legion
After he was defeated, his soul traveled to the Shadowlands. During the third invasion of the Burning Legion, the death knights of the Ebon Blade venture into the Shadowlands to collect the essence of darkness from his soul.

Arugal's monologue to Deathstalker Vincent

 * "I have changed my mind loyal servants, you do not need to bring the prisoner all the way to my study, I will deal with him here and now. Vincent! You and your pathetic ilk will find no more success in routing my sons and I than those beggardly remnants of the Kirin Tor. If you will not serve my Master with your sword and knowledge of his enemies...Your moldering remains will serve ME as a testament to what happens when one is foolish enough to trespass in my domain!"