The evolution is a result of Gyda fully corrupting Kieran's data, forcing him into a state of sleep. His body sleeps within the larva machine that's protected in the "Gehenna"/orb while his subconscious manifests in the form of the beast carrying it. Kieran's subconscious takes upon traits of Gyda, the mask upon his face helping keep Gyda from fully manifesting or taking control of the beast's body. All things considered, this digimon is more of a titan sized sleepwalker that's easily influenced by his dreams and heavy physical suggestions.