Fourarms

Fourarms was Ben favorite alien in the original series. His powers super streght. Fourarms was first used in "Washington B.C." Fourarms was used a lot in the series. In Ben 10 Ultimate Alien his appearance changed a lot. He looks more like a German fighter. He looks more like Tini (as seen in Galtaic Enforcers). Fourarms was first used in Ultimate Alien was in "Video Games" to defeat Ssserpent

Stinkfly

Stink Fly was first used in "Washington B. C." he can shoot goo from his eyes and mouth. He can fly to. In Ben 10 Ultimate Alien his appearnce did not change really at all. The Ultrimatrix Symbol was changed from his his head to his chest and turned green.

Grey Matter

Grey Matter was first used in "Washington B.C." he dosen't have any powers really hen 10 Ultimate Alien he just really small but he can stick to walls and climbs up. He is also really smart. He appear alot of time's in Ben 10 as a mistaken transformation. In Ben 10 Ultimate Alien GreyMatter ultrimatrix symboll change from his back to his chest.

Xlr8

Xlr8 first appeared in "And The We Were Ten." he can run really fast. In Ben 10 Ultimate Alien He does not really change just the omnitrix symbol turns green.

DiamondHead

Diamond Head was first used in "And Then There We Were Ten" Diamond Head ca shoot diamonds and shape sit with his hands. Diamond Head was one of the 6 aliens to reappear in Ben 10 Alien Force(the others were Cannonbolt,Upchuck,WayBig,and Ghostfreak) In Ben 10 Alien Force his appearnce has changed alot like his head and cloths turned dark blue and his diamonds just turn more darker.
His appearnce in Ben 10 Ultimate Alien is just like the same in Ben 10 Alien Force

Wildmutt

Wildmutt first appears in appears in "And Then We Were Ten" Wildmutt dosen't talk but he did talk in "Ghostfreaked" when he saves a little kid. In Ben 10 Ultimate Alien his appearnce dosen't not really change at all just the ultrimatrix was moved from his arm from his chest. Wildmutt dosen't have eyes but he has a sence on his neck that nakes him see

HeatBlast

Heatblast was the first alien that Ben ever used. He first appeared in " And Then There Were Ten" Heatblast appears in Ben 10 Ultimate Alien his appears as sltiley change. He looks more like Alan Albright alien form.