Colin was once a forensic pathologist that did a lot of work for the Gardaí, Ireland's police force before Scion. He was conscripted by SciSORS when Paige was eight and the two were forced to move to the Scion Citadel of London. He was asked to find a scientific explanation for why people become clairvoyant and why spirits linger after death. Paige notes bitterly that he believes clairvoyance to be an illness that can be cured.
Colin has red hair and is described as resembling Paige's cousin Finn McCarthy. Paige remarks that she looks nothing like him.