Defensor is an Autobot combiner formed from five Protectobots. He was created to protect the Tagan Heights from Devastator, though their one-on-one battle has caused some major destruction in the area. He was also a countermeasure against Decepticon combiners.
The Wreckers have apparently bought time for the Autobot scientists to create Defensor. Later two Destroyers have destroyed the Autobot facility where he was built in while chasing two Mini-Con saboteurs.