The Architect is a mysterious character who is often thought to be merely a myth which is how he likes it. His real name is Nathaniel.
He first appears in Deadlock.
He is mentioned at the beginning of the book but that is not realised until later on.
His pseuydom "The Architect" is first let slip by Matt Ronson, Raven initially dismisses him over this believing him to be a myth but Ronson states that he isn't. Nero then confirms this a little later and tells them how this man "The Architect" is a genius when it comes to designing bases for supervillains and works for whatever supervillains has the most interesting projects.
He is then later revealed to be callled Nathaniel and built Number One's space station, designed some of HIVE and other great stations like that. Raven, Otto and Diabolous have him taken to HIVE for his own protection after his assistant is revealed to be working for the Disciples. They are persued across Venice by the Artemis Section and the Disciples.
When they get back to HIVE, Nathaniel reveals himself to be Nero's father.