Avalon is a massive ancient floating fortress powered by a "Nova-class" Black Hole Engine and equipped with powerful defensive and offensive armaments. Given its size and presence of residential amenities, it is presumed to also provide field deployment and house its own garrison. It was created by the United Assembly during the Great War to act in two capacities: first, as a forward operating base in the front lines; and second, to bring a flexible approach to static defense, bolstering the strength of threatened core planets. Avalon participated in combat against Blue Flowers and to repel waves of Beasts. In a certain battle, Avalon suffered extensive damage that forced its decommission from further military service.
In CC 230, the humanitarian aid organization "PF" transformed itself into the Knights Order. It somehow acquired the damaged Avalon which was then used as the foundation for the Knights main headquarters, Core Temple, in Planet Arin.
In CC 430, Beast Queen E-34 hacked into Core Temple and Avalon. She repaired Avalon by replacing damaged parts with bionic elements capable of replicating the original functions. Avalon was then converted as a hybrid Blue Flower. The Core Temple's massive core and Avalon's Black Hole Engine, were repurposed into a plant capable of mass producing thousands of high rank Beasts and a number of Blue Flowers.