Okalin was a Confederate adviser to King Sanjay Rash of Onderon at the time of the battle that took place there during 20 BBY. He was present with Rash for much of the battle and when he threatened to kill former king Ramsis Dendup if he didn't call off the rebel attacks.
After the rebels rescued King Dendup, Rash, Okalin, and General Kalani took refuge in the throne room of the palace where Kalani ordered droid gunships to hunt down the rebels. When this failed, Okalin watched as Rash complained about the failure of the droids and asked for more reinforcements from Count Dooku.
Dooku, however, was not interested in keeping hold over the planet if it meant a long-term battle. He ordered Kalani to escape with the surviving droid forces to Agamar. Rash attempted to protest, but was shot and killed by Kalani. It is unknown if Okalin was killed by Kalani or the Rebels, or was evacuated with the other separatist forces.