Ultimate Alien X, Ben 10 List Wiki

Ultimate Alien X was the Ultimatrix's Ultimate Celestialsapien who doesn't exist. When asked if Ultimate Alien X is weaker than its regular version due to a mutation, Derrick J. Wyatt said that would be a dumb idea.

Diamond-Snare, Ben 10 List Wiki

Ben 10: Omniverse (video game) - Wikipedia

Ben 10 - Wikipedia

Jetray, Ben 10 List Wiki

Ben 10: Ultimate Alien (TV Series 2010–2012) - Episode list - IMDb

I made a chart of the weaknesses of the original 10, and according to the wiki, diamondhead is strongest alien, since he has only one VERY UNCOMMON weakness : r/Ben10

Ben 10: Ultimate Alien (Western Animation) - TV Tropes

Ben 10: Alien Force Episodes, Ben 10 Wiki

Ben 10: Alien Swarm - Wikipedia

The Sentinel, Ben 10 List Wiki

Vinewolf, Ben 10 List Wiki

Clocktomix, Ben 10 List Wiki