The Mission to Metalorn occurred during the Clone Wars when Anakin Skywalker was sent to Metalorn to stop the production of C-B3 cortosis battle droids by the Confederacy of Independent Systems. He succeeded in destroying the factory that produced them and captured the Separatist leader Wat Tambor.
After landing on the planet, Anakin infiltrated the facility and found out the Separatists weren't just manufacturing a few of these new droids, but building an entire new droid army. After reporting this, Jedi Master Yoda ordered Anakin to destroy the facility. While searching for Tambor, Anakin was confronted by two Dark Acolytes: the brothers Vinoc and Karoc. After defeating them in a lightsaber duel, Anakin eventually reached the factory power core. He planted a series of bombs and then continued his search for Tambor. He eventually found him, and after defeating his bounty hunter bodyguard Vandalor, captured him. He then made it out of the facility before it blew.
But as he escorted Tambor back to his ship, Anakin was confronted by a doppelgänger of Count Dooku. The two proceeded to duel. While it was evenly matched for a while, the doppelgänger began taunting Anakin with knowledge of his mother. Anakin struck the doppelgänger down in anger, and brought Tambor back to Coruscant.
Supreme Chancellor Palpatine had Tambor placed under the watch of his personal guards when Anakin returned with him. Anakin reported the results of his mission to Jedi Masters Yoda and Mace Windu, who were pleased with how the mission turned out.
- Star Wars: The New Droid Army (First appearance)