Engineer Tryan was a crew member of the cryosleep ship Stromos which crashed in the episode, 7.06 "Lifeboat". Specifically, his title was Engineer, Second Rank. His consciousness was downloaded into the mind of Dr. Daniel Jackson.
A dark star orbiting the Talthus sun would draw too close to the star. The resulting solar flares would engulf Talthus, destroying the planet. Therefore the people of Talthus built three ships to try and partially evacuate the planet before its destruction. The ships were not capable of faster-than-light travel, so the people of Talthus developed a cryogenic sleep process where their bodies were placed in a sleep state, while their consciousness was stored in a separate memory system to prevent extensive damage to their memories and intellect. Tryan was an engineer, second rank working with these cryogenic sleep systems on the Stromos. Once reporting to his superior, Officer Pharrin, that the compartment was secure, Tryan entered his own cryogenic sleep chamber.
En route to the new homeworld, Ardena, the Stromos crashed on P2A-347. Some of the chambers were damaged beyond repair, and the power was failing for several others, causing the sleepers' deaths. Pharrin, desperate to save these last survivors of Talthus, attacked SG-1 when they came to investigate the crash. He was able to download twelve souls into the mind of Daniel Jackson before hiding. One of those souls in Daniel’s mind was Tryan.
Each personality cohabiting Daniel Jackson’s mind emerged separately. Tryan “awoke” with a painful headache to find himself in a strange black room, his arms partially restrained by leather straps tying his wrists close to his waist, with strangers nearby. The woman was calling him “Martice” for some reason, so he quickly explained that he was merely a crew member, not a Sovereign. To his shock, he caught his reflection in the observation room one-way mirror, and discovered he did not recognize the body he inhabited.
After overcoming his initial shock, he was able to communicate with Dr. Fraiser. As engineer of the Stromos, Tryan was very helpful in explaining the intricacies of the cryogenic sleep process. However, despite the physical evidence in front of him, Tryan denied the safeguards could be overridden to allow his consciousness to be downloaded into another’s body. With horror, he realized the process could be circumvented if a sleeper’s body, such as his own, was dead. Now intermingled with the other souls, he regretted to inform Dr. Fraiser that the Stromos passengers could not be separated again. Before they could discuss the matter further, Tryan started hearing voices of the other souls sharing Daniel’s mind with him. He was pulled away from control just before Daniel himself briefly emerged.
Tryan had a higher pain tolerance than the other personalities, so when the headache became too great for Sovereign Martice, he was able to once again emerge, much to relief of Dr. Fraiser. Before they could discuss anything, Pharrin arrived. Tryan immediately stood at attention before his superior officer, pleasure and pride evident on his face. Pharrin explained about the crash and that the people of the SGC would be able to save the rest of the passengers of the Stromos, but it would require great sacrifice of Tryan and the other souls with him. Tryan resolutely vowed to make whatever sacrifice Pharrin asked of him. Pharrin explained that the rest of passengers would be saved by the people of the SGC and all would be taken to a new home, but it would require Tryan and the others to leave Dr. Jackson. Tryan agreed before being forced out of control of Daniel’s body by the personality of the Sovereign Martice. Even after losing control, Tryan was likely the voice arguing with Martice, insisting that Martice agree to the removal since Daniel’s body was never theirs to begin with and they needed to save the people of Talthus.
Daniel Jackson was returned to the Stromos and Tryan and the other souls were extracted from Daniel’s mind. As far as Dr. Fraiser could determine, Tryan and the others were successfully incorporated into Pharrin’s mind, where it was hoped the other survivors would be able to assist them once they were awakened from the cryogenic sleep.
--Aurora Novarum 12:34 26 Nov 2005 (EST)