O'Brien (Nineteen Eighty-Four)

O'Brien (known as O'Connor in the 1956 film adaption of the novel) is a fictional character and the main antagonist in George Orwell's novel Nineteen Eighty-Four. The protagonist Winston Smith, living in a dystopian society governed by the Party, feels strangely drawn to Inner Party member O'Brien. Orwell never reveals O'Brien's first name.

O'Brien is a member of the Inner Party and, like Winston Smith, works in the Ministry of Truth. There, he holds an administrative position that is so distant that Winston has only a vague idea of its nature. Winston suspects that O'Brien secretly opposes the Party. Eventually O'Brien approaches Winston with some leading remarks which seem to confirm Winston's suspicions. Winston finds the courage to approach him candidly, declaring himself an enemy of the totalitarian state. At first, Winston's intuition seems to be correct: O'Brien presents himself as a member of the "Brotherhood" seeking to overthrow the Party and Ingsoc. O'Brien invites Winston (who then invites Julia) to his flat where, as a member of the Inner Party he lives in comparative luxury. There he extracts a series of pledges from the couple that they are prepared to do anything to serve the Brotherhood, except (at Julia's protest) to separate from each other.

In truth, O'Brien is an agent of the Thought Police, and is completely loyal to the Party and to Ingsoc. He is part of a false flag resistance movement whose goal is to find thought-criminals (citizens who think something that is deemed to be unacceptable by the Party), lure them in by pretending to be on their side, then arrest and "cure" them.

O'Brien is next seen after Winston is arrested by the Thought Police. He reveals himself as he enters the cell by responding to Winston's exclamation, "They've got you too!", by commenting, "They got me a long time ago."

Over several weeks, O'Brien tortures Winston to cure him of his "insanity," in particular his "false" notion that there exists a past and an external, self-evident reality independent of the Party; O'Brien explains that reality only exists within the human mind, and since the Party controls everyone's mind, it therefore controls reality.

...
Wikipedia