Jyn served aboard Captain Kybo's personal attack ship, the Dianoga as well as his capital destroyer, the Demolisher. When the crew were not flying through space looking for new worlds to plunder, they retreated to their secret base of operations on the oceans of Tarnoonga.
On one occasion, Captain Kybo kidnapped the freighter pilot known as Jessica Meade. He kept her secured in his ready room on Tarnoonga, but Jessica escaped and ran directly into Jyn Obah. Jyn tried to grab a hold of her, but Jessica evaded him and ran back towards her freighter. Jyn gave chase and tried to stop her before she could enter the ship. Jess halted Jyn's advances by trapping him between the blast doors of her ship. Once incapacitated, she freed him and blasted off from Tarnoonga.
Later, Jyn discovered that Captain Kybo had been arrested by King Mon Julpa of Tammuz-an and held prisoner at the royal palace. He snuck onto the planet and broke Kybo out of his cell. They managed to temporarily avoid detection by disguising themselves as natives of Tammuz-an. Soldiers under the command of Mon Julpa and Lord Malameu Toda eventually discovered their plot and gave chase. They managed to capture Jyn Obah, but Captain Kybo escaped.
Jyn Obah was a large alien of unknown lineage. He had tan-colored skin, long brown hair and two fangs projecting upward from his bottom jaw. He wore stormtrooper armor—none of which fit him properly. He also wore a black body glove, which likewise, was several sizes too small. His most distinguishing accoutrement was a large hoop nose-ring, which he wore through both nostrils.
He was voiced by Dan Hennessey.