"Dohmler told Warren we would take the case if he would agree to keep away from his daughter indefinitely, with an absolute minimum of five years" (2.4.1).
We lose sight of Devereux pretty much right after this. He’s been banished and only turns up again in the flesh briefly when he’s supposedly on his death bed. Yet,, once we meet him he never really leaves the novel. He is the past that haunts everything.