Dr. Terrance Kyne was the Chief Science officer aboard the USG Ishimura. A devout and high ranking Unitologist, he was selected by the Church of Unitology to to investigate and ultimately bring back the Marker found on Aegis 7. He was installed on the USG Ishimura in a role to facilitate this task, hence his prior knowledge of the Marker, and his close association with the Isimura's captian, Benjamin Matthius and fellow scientist Dr. Challus Mercer. At some point in the past, he was married to a women named Amelia, who died prior to his coming on the mission.
When the USG Ishimura arrives at Aegis 7, Kyne becomes skeptical of the Marker. He (correctly) believes that there is a connection between the murders, suicides and general unease of the colony, with the Marker. He is also one of the first to directly study the marker once it is brought onboard, which begins to confirm his beliefs. As such, he began to question the claims of the Church and the divinity of the Marker. His objections with the Church and with the mission put him at odds with Captain Metthius. Once the Necromorphs are discovered, he demands that the Marker be returned to the colony, however Captain Metthius remains adamant that it should remain on the ship for further study.
By this point, the infestation of the Ishimura has already begun, and many of the crew, Kyne, and Captain Matthius included, have begun to lose their sanity from their proximity to the Marker. Kyne sees the true horror of the Necromorphs and denounces the Church, meanwhile Captain Matthius was becoming increasing paranoid and erratic, demanding the the Ishimura return to Earth, despite the fact that the ship was infested with Necromorphs. Kyne declares the Captain mentally unfit, and relieves him of duty. However, whilst trying to sedate Matthius with a needle, a struggle ensues, and Kyne stabs him in the eye, killing him.
Kyne, now fully insane, ejects all the escape pods and shuttles off the ship so that no one may escape, or more importantly, no Necromorphs could escape. He also disables other key systems of the ship in order to further ensure that the ship never leaves. He believes that this is the only option. After sabotaging the ship, however, he receives hallucinations from his deceased wife telling him that by returning the Marker to Aegis 7, the Necromorph threat will be eradicated. Ironically, the systems and shuttles that he sabotaged in an attempt to contain the Necromorph threat prevent him from doing just that. It is up to Isaac Clarke to restore many of these systems during the course of the game. Kyne eventually reveals himself to Clarke, asking for his assistance in returning the Marker to the planet. Eventually Isaac gets a shuttle operational, and he and Kyne are about to bring the Marker to the planet, when Kendra Daniels betrays them both and shoots Kyne, killing him.