Gwen, watching the battle unfold, quickly formulated a plan. "Ben! The Omnitrix's symbol! It's connected to the Temple somehow. You need to unlock its full power!"

Ben, shifting back to his human form, nodded. He slammed his hand on the Omnitrix, but instead of selecting an alien, the watch pulsed with energy, syncing with the symbols etched into the Temple walls. A deep rumble shook the ground as the Omnitrix's true power awakened.

In a flash of green light, Ben transformed into Infernus, a fusion of his fiery alien forms with an ancient cosmic energy. His body was wreathed in flame, but his power was now on par with Ignis.

Infernus (grinning): "Time to turn up the heat!"

Ignis, sensing the shift in power, stepped back, his eyes narrowing. "Impossible... you cannot wield the Eternal Flame's power!"

Infernus (charging forward): "Watch me."

The battle that followed was an explosion of raw energy, fire, and cosmic forces. Ben, now wielding the full potential of the Omnitrix, overwhelmed Ignis with a series of devastating blows. Finally, with one last powerful strike, he shattered Ignis's fiery form, sending him spiraling into the void.