The first season (Episodes 1–20) focuses on two major shifts: Ben’s secret identity being leaked to the public by young fan Jimmy Jones, and the arrival of the Osmosian villain .
To stop a fully powered Aggregor, Kevin Levin makes the ultimate sacrifice, absorbing the Ultimatrix's energy. This saves the universe but drives him insane, turning him into Ultimate Kevin and forcing Ben to consider a lethal solution to stop his best friend. Season 2: New Allies and Galactic Threats ben 10: ultimate alien all episodes
This season introduces Eunice , a "living Omnitrix" who absorbed Gwen's DNA, and sees the return of Ben 10,000 . The first season (Episodes 1–20) focuses on two