This page contains information regarding Star Trek: Discovery, and thus may contain spoilers.
Ryn once attempted to rally the people to rebel against the Emerald Chain's leader, Osyraa. As punishment, she had Ryn's antennae hacked off and condemned him to the salvage yard on Hunhau, where he was forced to implant explosive control devices on the slave laborers. Ryn attempted to help the laborers in what small ways he could, but was treated as a pariah by all sides.
In 3189, Ryn befriended Cleveland "Book" Booker after the latter was captured by the Emerald Chain. He subsequently assisted Book, Commander Michael Burnham, and Philippa Georgiou in breaking the laborers out of the salvage yard. During the escape, he shoved Book out of the path of a hand cannon blast, taking the hit himself. He and Book were beamed to Booker's ship and taken to the USS Discovery in time for Doctor Tracy Pollard to treat the wound. (DIS: "Scavengers")
Ryn's escape vexed Osyraa, because he knew the Emerald Chain's secret: they were running out of dilithium. At Kwejian, she realized that Ryn was aboard the USS Discovery, and attempted to force Captain Saru to relinquish him by attacking the Sanctuary. Despite his distrust of the Federation, Ryn helped Lieutenant Keyla Detmer disarm Osyraa's flagship Viridian from Booker's ship. Afterwards, he reevaluated his opinion and told the Emerald Chain's secret to acting First Officer Sylvia Tilly. (DIS: "The Sanctuary")
Ryn was still aboard Discovery when Osyraa hijacked it outside the Verubin Nebula. When Osyraa took Discovery to Federation Headquarters, Ryn helped the crew by hacking into the computer and making the internal sensors show every single person from the prior three months. Osyraa executed him on the bridge when he refused to correct the system. (DIS: "Su'Kal", "There Is A Tide...")