Nathaniel Essex - Character Guide

Dr. Nathaniel Essex — the character comics readers know as Mr. Sinister — is a former teammate who finds Logan living in the wilderness and recruits him back to Team X. Essex presents himself as a protector: he is building a sanctuary for displaced mutants away from society's prejudice, and the push-pull between rescuing mutants and ending the abductions drives the first two acts.

Troy Baker (Joel in The Last of Us, Higgs in Death Stranding, Booker in BioShock Infinite) plays Essex, and reviews consistently rank his vocal work among the game's standouts. The performance sells the ambiguity — for most of the campaign you are never quite sure whether Essex is the solution or the disease.

Essex is the last boss of the game: A Sinister End unlocks after Mission: No Coming Back, the two-part finale in the Madripoor act. The fight assumes a late-game Logan — see the Essex boss page for the encounter breakdown, and treat it as the campaign's final exam.