When Mace Windu requested Jedi to accompany him to Geonosis in order to rescue Obi-Wan Kenobi, Agen and his Padawan Tan Yuster volunteered. Agen fought well in the arena, but Tan was killed before Yoda's gunships arrived to rescue the survivors of Windu's task force. He continued fighting bravely in the Battle Of Geonosis despite his loss.
When Anakin Skywalker informed Mace Windu that Chancellor Palpatine was actually a Sith Lawd, Agen joined Saesee Tiin and Kit Fisto in accompanying Windu to arrest the Chancellor. Immediately after confirming that he was indeed a Sith, Palpatine ran Kolar through with his lightsaber.