Ethranax was a controversial decision by the PPDC. They took the corpse of a dead Kaiju and retrofitted it with rudimentary weaponry on its head and arms. Why? Well, the answer is simple. Most Kaiju are weak to machinery, and ones from the Antiverse (Breach) fear machines. Ergo, seeing one of their own turned into what they view as a "demon" is essentially a form of psychological warfare.

However, there was a massive oversight. As observed by scientist and groupie Newton Geiszler, the hive mind doesn't fully dissapate after death, and as soon as Ethranax was resurrected by the PPDC for use as a living weapon, the bond between it and its brethren began to slowly "wake" from its dormancy. It wasn't long before Ethranax turned on humanity a second time.

After its full resurrection, Ethranax encountered Stormbringer Gojira, seemingly unaffected by Zero's influence. Ethranax and Gigan are currently Stormbringer's only trusted and true allies.