Eidolon is a term used for Combatuids who have reached phase2 in their transformation and posess the ability of flight. Of the 20 combatuids of The Dome, only two of them reached the Eidolon level: Dragunov and Jorus. 4 combatuids were hatched with default wings: Gatling, Lodos, Aventador and Visaus. 3 Combatuids were also upgraded by the enhancement granted by the black dragon Baran-Dur: Ardonin, Antonov and Joland.
Eidolons are mechanically created from the same material as combatuids with the absence of an Orb. The missing orbs were collected from the fallen combatuids.
Of the last 3, Ardonin's sphere was used to create directly new Eidolons in the service of The Resistance:
The next step in the evolution of a combatuid is Avatar.