Wat Tambor was an NPC, an alien Separatist leader.
Silence of the Clones Edit
At the Separatist leader conference Obi-Wan was eavesdropping on, he declared that he should be made leader after the Republic was overthrown.
Revelation of the Sith Edit
He was slaughtered along with all the other Separatist leaders on Naboo by Anakin.