Demona is an immortal gargoyle determined to wreak vengeance upon all humanity for humans' crimes against the gargoyle race.
(938 - ?) Back in 994, Demona was Goliath's great love. However, she betrayed Castle Wyvern to Hakon's Vikings, causing the Wyvern Clan to be destroyed and Goliath and the survivors to be frozen in stone. She left Wyvern and unwittingly created the first Hunter, and over the next few decades she lived with a band of gargoyles who survived other massacres as their leader.
In 1040, she made a bargain with Macbeth and the Weird Sisters in which she regained her youth in exchange for helping Macbeth slay Duncan and become king of Scotland. Seventeen years later, Duncan’s son, Canmore, returned with an English army, and Demona, falsely believing Macbeth would betray her, deserted him. In the process, her clan was destroyed, and the immortality she shared with Macbeth was revealed.
She spent the next few centuries planning her war on humanity and gathering useful tools, like the Medici Tablet and the Praying Gargoyle. She encountered Puck and was later introduced by him (as Owen Burnett) to David Xanatos. Together they raised Castle Wyvern to the top of the Eyrie Building and awoke Goliath and his clan.
Demona helped Xanatos use the gargoyles to steal three computer disks from Cyberbiotics to complete the Steel Clan robots. When Goliath refused to help her make war on humanity, she declared Goliath as her enemy. Over the next year, Demona enacted many schemes against the gargoyles- she used Brooklyn in an attempt to enslave Goliath through sorcery, she attempted to poison Elisa Maza, and, with Xanatos, she resurrected her rookery brother as the cybernetic Coldstone.
She later stole Titania's Mirror and tried to make Puck her slave, but all her commands backfired, and she was cursed with becoming a human by day. She used the Phoenix Gate in an attempt to change history, but learned that history cannot be altered. Soon after, Demona cast a city-wide spell turning everyone to stone throughout the night, but Xanatos and the gargoyles stopped her. She and Macbeth were taken by the Weird Sisters to steal the Eye of Odin, the Phoenix Gate, and the Grimorum Arcanorum for the Archmage (her once-tutor in sorcery). They were used by him as cannon-fodder against the Avalon Clan, but were freed and cast out of Avalon to Paris, where Demona met and fell in love with Thailog and set up Nightstone Unlimited.Angela and Elisa. Demona retained the Dominique Destine identity and acted as the public CEO of Nightstone.
Thailog and Demona next tricked the Manhattan clan into capturing Demona and locking her in the Labyrinth, where she used a robotic mosquito to steal DNA from the clan. She also met and came to love her daughter Angela, whom she knew about earlier thanks to Dr. Anton Sevarius. Thailog rescued her, and they trapped the clan in a funhouse and introduced them to their clones. When Thailog attempted to kill Angela, Demona fought him, and Thailog brought out a clone created with Demona and Elisa's DNA named Delilah. Enraged, Demona battled Thailog and they both seemingly perished in a fire.
Demona resurfaced later around the same time three new Hunters appeared in Manhattan. She created a powerful spell that she would use to destroy the human race, and use the Praying Gargoyle to protect her race. When the time came to finally destroy humanity, Goliath destroyed the Praying Gargoyle. She fled before she could be captured and has not been seen since.
Greg Weisman's Master Plan
Demona would have continued plotting against humanity and the Manhattan Clan. She would have turned her attentions toward Angela as well (Angela hoping to redeem her mother). In the year 2198, she'd end up joining Samson's resistance against the Space-Spawn and would have gone into space with Nokkar, Nicholas Natsilane Maza, Zafiro and LXM-1057. She'd also have had two more great loves, though their identities are currently unknown. At some unknown point Demona would have had an epiphany and realized she was at fault for the massacre.)
The Goliath Chronicles
Demona attempted to become the leader of the Manhattan Clan and have Goliath killed with the help of the Assassin, but this plan backfired, distancing Demona from her clan and her daughter even further.
Demona was the final boss faced by Goliath.