As the Separatist Crisis intensified, lead engineer Wat Tambor of the powerful Techno Union met in secret with Count Dooku and other Separatist sympathizers. Tambor pledged the Techno Union’s resources to the Separatist cause, boasting that the organization’s battle droids would give Dooku the best army in the galaxy.

When the Separatists invaded Ryloth, Count Dooku installed Tambor as the Twi’lek homeworld’s emir. Tambor looted the planet and viciously subjugated the Twi’leks. When a Republic task force assaulted the Separatist blockade, Tambor reminded Neimoidian commander Mar Tuuk that he could not allow the defenses to fail.

After Tuuk repelled the first Republic attack, he reported to Tambor – who congratulated him on the victory but warned the Neimoidian not to underestimate the task force’s commander, Anakin Skywalker.

Skywalker’s second attack succeeded, and when Tambor contacted the blockade’s flagship, he was enraged to discover Tuuk had fled. The Republic began landing its invasion forces.

With Tuuk having failed, Tambor replied on a tactical droid, TX-20, to defend Ryloth against a Republic assault. The droid used Twi’leks as living shields to protect his proton anti-aircraft cannons in the city of Nabat. But the clone troopers defeated TX-20 with the help of Numa, a young Twi’lek refugee.

With Republic invaders advancing across Ryloth, Tambor found himself trapped in the capital city of Lessu. His lieutenant, tactical droid TA-175, recommended a retreat, but Tambor indignantly refused. Noting that Mace Windu lacked sufficient troops to take the city, Tambor ordered ground forces brought inside.

TA-175 contacted Dooku, who told Tambor he was no match for Windu. The count ordered the Skakoan to strip Ryloth of its treasures and leave the charred ruins of the Twi’lek planet as a demonstration of the cost of a Republic victory. But to Dooku’s disgust, Tambor moved slowly, greedy to loot as much as he could.

Tambor would regret the delay: He was caught in Lessu when the Republic attack came. TA-175 fled in an escape craft, leaving Tambor behind. Windu and Twi’lek freedom fighter Cham Syndulla then took the emir prisoner.

Freed from Republic custody later in the war, Tambor rejoined the Separatist war effort. But the tide was turning against Dooku’s forces. Tambor and other Separatist leaders were forced to retreat from planet to planet, taking refuge on Utapau before being sent to Mustafar.

Tambor was on Mustafar when Darth Vader arrived with orders to eliminate the Separatist leadership. He impaled the Techno Union leader with his lightsaber, killing him.