New Century Zero has a number of animation cameos with Zoids from Chaotic Century and Guardian Force, which are the cause of much fan speculation but not explained. Moonbay's Gustav can be seen in the background in one of the later episodes, the Backdraft shoots judge satellites down with a Death Stinger tail, the Death Saurer appearing as a model and in a background TV show, the three Geno Saurers that attack Berserk Fury, and the Ultrasaurus wreck on which Bit Cloud claims victory carries the Gravity Cannon on its side.