Although there is no mention of any Zoid known as an Ultimate X in these series', when an Organoid merged with a Zoid it produced very similar results: increased strength, speed and stamina, as well a degree of sentience (this, however, is the sentience of the Organoid in the Zoids, not the Zoids themselves). There is speculation that the Organoid System seen in Zoids: New Century is in fact the evolution of the original Organoids seen in these series', permanently fused with a Zoid. Although this explains the apparent sentience and even the personality of these Ultimate X's, there is no proof to show that these are not two completely different systems.