B.A.KA
While he had the heavy firepower, and surprisingly the skill to use it, the Devil Gundam it self simply was not fast enough to keep up with ether of the lighter and faster Gundam.
"Well, I figured this would happen if I had to deal with both of you at once." He said as the the Gunpla started to regenerate the damage. "Oh well. I planned for this as well." He said with a smirk. "You can thank your friend, the American champ for this one, and since we're quoting non-GUndam anime for this, I have the perfect line, a very fitting line given the power gap that's about to form." The Devil Gundam swatting away the German champs Gunpla and taking a few more pot shoots at Dani but then stopped moving completely.
"Bankai"
The Devil Gundam glowed for a moment, and unlike a normal 'DG Cell' transformation, was swallowed by a swirling dome of light, that shrank a bit before vanishing in a flash of light revealing a more standard sized Gunpla, no bigger then the God Gundam or Shadow Gundam. This new Gunpla was a mix of the Devil Gundam's final form and the Reborns Gundam from 00, and a normal pair of legs, clearly taken from the Reborns. The yellow 'nobs' that adorned the shoulders and back of the Devil Gundam where replaced with GN Drives, though slightly smaller, and there was even two more on each leg.
"Ultimate Gundam; Reborn."
Alexis went white as sheet. "Not possible ... H-How ... that should be on a shelf an ocean away ..."