We first hear of Oliver Peach under his Drek’s Game pseudonym.
Oliver, along with his brother Charlie, are members of The Halvening, a far-right terrorist organisation that is targeting right-wing victims, mostly women, either directly with pipe bombs or by spreading lies about them on the internet and other types of harassment.
We first see Oliver outside the game at ExCeL for the 2015 Comic Con, where Strike thinks he is acting suspiciously. He is described as “a young man in a leather jacket, jeans and expensive red-soled trainers” (Ch 56).
His name is later revealed by the BBC News website as they are reporting on the incident that befalls him at the train station. Strike realises that his Drek’s Game username is an anagram of Oliver’s real name and passes this information to the police.