Luke Reader was the triplet brother of Gideon Reader and Catherine Reader. He looked like Gideon, but with glasses, and used to live with his foster mother on the Isle of Wight. At first, Dax Jones was jealous of Luke because of all the attention Gideon gives him, but he forced himself to respect the newcomer, and tried to accept that 'Gideon and Dax' was going to become 'Gideon and Dax and Luke'.
He first appeared in Running the Risk, at Tregarren College. He was considered a "dud", not exhibiting any supernatural powers, except for an incident in the dormitory, where he broke the glass in the window by accident with his mind. Nobody realised it was him except Dax. He then shows his powers at the end of Running the Risk, by holding a wave with his mind, one that Catherine would have used to destroy the other COLAs, thus saving them. He then let the wave crash down, and Catherine took him away with her.
He was a telekinetic like Gideon.
In Dowsing the Dead, when the COLAs found Luke again, they realise that he was mute, as Catherine had somehow shut down the speech centres of his brain, rendering him mute.
When Catherine took Luke away, she goes to Nice in France, and imprisons him there after wrenching his tongue and making him forget how to speak so he could be a mute. In feather and fang, he is learning to speak again, but prefers not to, as it requires effort and concentration.