He is a 15 year-old who is planning to run away from home, looking for adventure. But unfortunately, sometimes people do get what they wish for. Ryan was in the library when he discovered a key, and then was set upon by a bunch of scary, nihilistic punk-sorcerers who needed him to set off a doomsday device that will destroy the planet and everyone on it. He also had a crush on Valkyrie.
He later finds out that he doesn't exist. Deacon Maybury had created Ryan as the perfect hiding place as no one would suspect an ordinary boy to actually be a sorcerer. Torn apart, he has no idea what to do. But later he decides to help Skulduggery and Valkyrie dismantle the bomb, just to annoy Deacon. After Valkyrie kissed him briefly, he disappeared and Deacon returned.
It is hinted throughout the story that Ryan isn't what he appears to be. Skulduggery deduces his true identity before or shortly after the group arrive at the shopping centre.