Once a Hynerian Dominar, the ruler of over 6 billion subjects, Rygel was a great leader, in a long line of Rygels, but was deposed by his cousin, Bishan, and put in prison. After a hundred cycles in Peacekeeper captivity, Rygel has learned how to survive, and can often come across as very selfish at times, but he is perhaps the most wise being aboard Moya. Rygel was largely responsible for the successful escape attempt in Premiere, as he was able to move around Moya through hidden passages in his cell.

It never seems as if Rygel makes friends aboard Moya, though he clearly grows closer to Pilot, and seems to have a decent relationship with both Zhaan and Chiana. He is only just tolerated by Aeryn, who often threatens to chuck him off the ship, whilst John and D'Argo clearly don't worship him, though they do concede that the little Hynerian has his uses from time to time.

There are a few key episodes for Rygel, including his time as a ruler in Jeremiah Crichton, where the local inhabitants were clearly an abandoned colony under the rule of the Hynerian royals. He also encounters his former torturer aboard the wreck of the Zelbinion, Captain Durka. Though he at first believes the man dead, he sees him alive in Durka Returns, and fighting begins (resulting in Rygel undoing the 100 cycles worth of mind cleansing the Nebari had imposed on Durka).

The pair meet again in A Not So Simple Plan, and this time Rygel emerges victorious, placing Durka's head on a stick. Rygel has many other impressive moments as well, especially when it comes to royal diplomacy, for example in A Kiss Is But A Kiss, when he gets the crew allowance to visit the royal planet, and later when he manages to pursuade the Empress to help their cause. However, he has his weak moments too, abandoning the crew when necessary (Family Ties), and sabotaging the crew's hopes when it doesn't suit Rygel (Could'a Should'a Would'a)>