This is my first proposal under the new format. Here I am proposing another Gargoyles villain, and arguably the one who probably set the heinous standard for the show. What do you have to say about Hakon?
Who is Hakon? What Has He Done?
Hakon is the leader of a group of Vikings looking to raid Castle Wyvern and subject its residents to slavery. In the year 994 AD, Hakon launched an attack to the castle, but the Wyvern clan awaken from their stone slumber with Goliath leading the defense against the Vikings. After getting overwhelmed by the gargoyles, Hakon takes his men to retreat, vowing vengeance. After conspiring with the castle's Captain of the Guard (who just wanted to ensure the clans safety and freedom from the humans and their ridicule), Hakon leads another raid with the Captain sabotaging the bows and arrows and successfully take Princess Katherine, Magus, and the poor folk prisoners. Not satisfied with simply raiding the castle, Hakon slaughters most of the Wyvern clan while they were stone. The Captain tried to intervene against this, but Hakon threatens to kill him if he got in his way, remarking that he didn’t live this long by taking foolish chances, then shatters the clan except for Goliath and the gargoyles in the rookery who would eventually become the Manhattan Clan a thousand years later and Demona, who hid and conspired with the Captain to rid the castle from the humans.
While at a camp, Hakon starts burning spells from the Grimorum Archanorum book (with one of those spells being a reverse spell to awaken the clan from eternal stone slumber) to spite Magus. Goliath vows vengeance against the Vikings, believing that Demona was killed in that raid. As soon as Goliath corners Hakon and the captain toward a cliff, the captain tried to explain his actions, but Hakon immediately passed the blame to the captain for the massacre, which he did not take well ("YOU LYING SCUM!"). Hakon and the captain started fighting which had them falling off the cliff to their deaths.
Episodes later at the beginning of the Avalon world tour, Goliath was haunted by visions of the massacre. Hakon and the Captain's souls still linger in the castle, kept there with hatred toward Goliath. They proceeded to torment Goliath with visions of the massacred clan blaming him for their demise. Goliath starts seeing that something is amiss when one of those visions was Demona. Hakon and the Captain start a ritual that would revive them and bind Goliath's soul in the castle for all of eternity. After Goliath asks what good is living without honor to the Captain, the Captain thwarts Hakon's ritual, realizing that the hatred he kept was toward himself for betraying Goliath. After stopping Hakon's plan, the Captain thanks Goliath for redemption and proceeds to the afterlife while Hakon was still stuck in the castle, keeping his hatred toward Goliath.
In "Vendettas," his soul wound up being bound to a battle axe with his descendant Wolf (Gargoyles) wielding it, trying to kill Goliath and Hudson. After Wolf got defeated, Hakon possessed him to get a shot to destroy the gargoyles himself. Of course Wolf did not take kindly to Hakon possessing him. Eventually, the battle axe got destroyed when it was lured to a car compactor, presumably sending Hakon straight to Hell.
Hakon is a remorseless bastard who is motivated by vengeance and hatred, showing contempt to those who oppose him. He didn’t even show love to Wolf, his descendant, calling him "a disgrace to the bloodline."
Arguably, you can say that Hakon set the standard for how evil a villain from Gargoyles can get. He is a mass murderer, killing most of the Castle Wyvern clan while they were helpless, and sought out to trap Goliath for all of eternity. His motivations are done out of pure greed and hate.
If you think about it, Demona would not be as she was if it were not for Hakon’s actions. After the massacre and Magus putting Goliath and the clan into an eternal stone sleep (done out of grief presuming that Princess Katherine died and Magus was blaming the gargoyles), Demona was the one who created the Hunter and committed many atrocities throughout, but it was Hakon who has sewn the seeds of hatred. So in a sense, he’s indirectly responsible for making Demona vengeful toward humans and having her commit such atrocities like having the citizens of New York turned to stone at night so she can kill them just like how Hakon killed the Wyvern clan.
Hakon has no excuse for his actions and is motivated by hatred toward Goliath, blaming him for his death when it was his own fault.
When it comes down to it, I believe Hakon qualifies.