Castle Wyvern was constructed in 971 on a cliff above the caverns where a clan of gargoyles- later known as the Wyvern Clan- dwelled. The clan agreed to defend Castle Wyvern and its inhabitants from attack by night in exchange for protection by the humans of Wyvern by day. From 971 to 984, the castle was ruled by the human Prince Malcolm. Malcolm was advised by the wizard known as the Archmage, until he attempted to take over, whereupon Malcolm banished him.
After Malcolm's unrelated death some time later, the castle was ruled by Malcolm's daughter, Princess Katharine, who was advised by the Archmage's former apprentice, the Magus, and Wyvern's Captain of the Guard. Unlike her father, Katharine had nothing but contempt for the clan of gargoyles protecting the castle, which eventually led to Demona and the Captain of the Guard's betrayal of Castle Wyvern to a group of Vikings led by Hakon in 994. The castle's inhabitants were all captured and taken away by the Vikings, and all the Wyvern clan- save seven gargoyles- were massacred. After Goliath and his clan were placed on the parapets in stone sleep and the eggs in the Rookery evicted, the castle was abandoned.
In 1994, Castle Wyvern was moved from its original location to rest atop the Eyrie Building in Manhattan by industrialist David Xanatos. After it was moved, the castle's interior was modernized, although the original structure of the castle was preserved. As a result of the incredible height of the Eyrie Building (it stretched higher than the cloud cover), the terms of the spell that ensorcelled Goliath's clan in stone- that they would remain so until the castle rose above the clouds- were fulfilled. Thus, the clan awoke.
Castle Wyvern remained the home of Goliath's clan until they were driven out by Macbeth. From then on it was the home of Xanatos and his family. By the time Goliath, Elisa Maza, and Bronx had disappeared on the Avalon journey, Xanatos added concealed laser cannons in several of the castle's towers. They were used against the Trio and Talon, but the four destroyed them.
After the battle with Oberon and the Hunter's Moon incident, the Manhattan Clan moved back to Castle Wyvern once more, sharing it with their new and unexpected allies, the Xanatoses. They still live there at present.