Engine Defenders: Extreme is the 2014 sequel to Engine Defenders.
One year after the DarkGlass Empire was defeated, a new evil emerges to take its place; the Crisis Zone Army. Coming from the Crisis Zone, this new army is made up of four planetary forces; the armies of the planets of fire, ice, earth and water. Assembled by the Great Crisis Emperor Overlord, the new armies eek to steal Earth's resources in order to breathe new life into their dying worlds.
In order to oppose the threat, the Engine Defenders team are reformatted with new vehicle modes as well as an entirely new team member; the female Firecracker, and then set out to combat the Zone Army.
Automus: He is reformatted as a fire truck. His relationship with Blitz and his leadership skills have improved since the previous series. Voiced by Garry Chalke.
Thrust: He is reformatted into police car. He remains best friends with Tracks, and they still tend to annoy Blitz, although he has since grown used to them. Voiced by Christopher Daniel Barnes.
Brawl: He is reofrmatted as an ambulance, with much less yellow. He is still like a brother to Thrust, and cares very deeply for him. He has also begun to view Tracks as a brother too, or atleast a nephew, as he points out. Voiced by Jeff Bennett.
Blitz: Although he is only upgraded to a newer tank mode, Blitz is still skilled fighter and carries an incredibly powerful arm cannon. He has also grown fond of Thrust and Tracks' pranks, although they do occasionally still annoy him. Voiced by Bruce Greenwood.
Tracks: He is reformatted as a jet. This is a flipside to the previous series, in which Tracks was jealous of Thrust's vehicle mode, and now Thrust is jealous. Voiced by Bumper Robinson.
Firecracker: A flirtatious new motorcycle, she has grown closest to Automus over the course of the series. She wields a mace in battle. Voiced by Mae Whitman.
Crisis Zone Army
They come from the Crisis Zone to terrorize Earth.
Overlord: The tyrannical leader of the Zone Army, he allies the four, previously warring palnets together to steal energy from Earth. His true plan is to devour the four planets and form a new body. He creates a temporal body to face the Bots on Earth while his true form prepeares to consume the four planets. However, Joker turns against him and blasts him, causing him to collapse into a black hole. Voiced by Michael Ironside.
Prince Pyrus: The ruler of the Fireworld. His father vanished mysteriously in battle years ago, and Overlord has promised to reunite the two in return for his allegiance. After learning the truth that his father had perished, he withdraws his troops during the final battle. Voiced by David Koseruba.
Trident: King of the Waterworld and father of Hysteria. He dies in a particularly brutal battle against the Bots, leaving Hysteria to take control. Voiced by John Noble.
Lord Mantel: Ruthless and arrogant ruler of the Earthworld, Mantel sees the other world rulers as beneath him. This ultimately cost him his life, as he attacked Earth alone and was impaled during a duel with Automus. Voiced by Frank Welker.
King Cryos: Cold hearted king of the frozen Iceworld, he is jealous of the lavish summers that Earth enjoys and enters a pact with Overlord to bring summer the Iceworld. He is later absorbed by Overlord before the final battle. Voiced by Charlie Adler.
Queen Hysteria: Daughter of Trident and far more ruthless, she takes over as ruler of the Waterworld after her father's demise. After a battle with Firecracker on Planet Bone, she falls into a crevice to her death. Portrayed by Bridgit Mendler.
Joker: He is one of the last living members of Planet Bone, the planet of death. The four other rulers are unimpressed when he joins them, but turns out to be the last survivng meber of the council. He betrays Overlord in the finale, preventing him from destroying the four planets and causing him to collapse into a black hole. Joker then sacrifices himself, along with his planet, to close the black hole. Voiced by Tom Kenny.
The opening song was written and performed by the metal band Dragonforce, after the theme for the previous series was performed by Twisted Sister.