The third installment in the main Ben 10 series. It premiered on April 23, 2010, with its final episode airing in the United States on March 31, 2012. The series consists of two seasons totaling 52 episodes. Originally slated to be titled "Ben 10: Evolutions," the story is set chronologically after the events of "Ben 10: Alien Force," with Ben, Gwen, and Kevin each being one year older than in the previous series. The story picks up after the conclusion of "Ben 10: Alien Force," with Ben's transformation device having been upgraded from the Omnitrix to the Ultimatrix. At the beginning of the story, Ben's ability to transform into aliens is no longer a secret as it was in the past; the news has spread through the media, sparking widespread discussion. Ben, Gwen, and Kevin continue to work together as they did in "Ben 10: Alien Force," handling various crises, with the key difference being that they are now public heroes. In addition to Ben being able to transform into more powerful and diverse aliens, Gwen and Kevin also possess more varied abilities. Beyond facing dangerous enemies, Ben's challenges include navigating his relationship with Julie, which is tested by his newfound fame and unfriendly media attention. The main storyline of the first season revolves around the issues arising from their fame and the need to thwart the plans of the new enemy, Aggregor. The second season continues to explore Ben and Julie's relationship while also dedicating several episodes to individual character stories. The primary antagonist in the first season is Aggregor, while the second season does not focus on a single specific foe, instead featuring many returning enemies and new adversaries. In the later part of the second season, the nearly disbanded Forever Knights are reorganized, and the newly introduced Diagon emerges as a significant threat, connected to the return of Vilgax.