I recommend two novels,"Gang Zong: From the Master of the Ghost King Da" and "Strategy for the Villain Female Lead". They were both infinite in the universe and light novels derived from doujinshi. They both mentioned "Big Circle". In "Gang Zong: From the Master of the Ghost King Da", Big Circle Leopard was the big boss of the main character, while "Strategy for the Villain Female Lead" was based on the theme of "Top Ten Villains Starting from Tokizaki Kuzo", which included the world of Big Circle. I hope you like my recommendation. Muah ~