However, a new threat emerges. A rogue alien named Ragnarok escapes a Plumber prison. During the confrontation, Kevin discovers that Ragnarok was responsible for his father’s death. Blinded by vengeance, Kevin attempts to kill Ragnarok, crossing a moral line that disturbs Ben. Though Ragnarok is defeated, a rift grows between Ben and Kevin regarding the rules of heroism.
: Vreedle Brothers repo men try to reclaim Julie's pet, Ship. Single Handed all ben 10 alien force episodes
In the final confrontation, Kevin makes a sacrifice. To stop Aggregor, Kevin absorbs the energy from the Ultimatrix, mutating him into a monstrous form once again. But this time, the power drives him mad. He defeats Aggregor but declares himself a god, threatening to kill Ben to keep the power. However, a new threat emerges
: Big Chill takes over Ben's body to build a nest and lay eggs. Undercover Blinded by vengeance, Kevin attempts to kill Ragnarok,
An older, future version of Ben (Ben 10,000) appears to warn about a time-traveling villain named Eon. This episode connects Alien Force to the future timeline. Key moment: The concept of “Ultimate Ben” is introduced (later explored in Ultimate Alien ).