Farley Havelock

"Did you think I'd fight you Corvo? Sorry to disappoint... This is yours the key to Emily's cell, she'll be glad to see you. You made quite an impression on her did you know that? She asked about you constantly where you were, what you'd been doing. I told her... In the end I told her everything. From the start when we had such noble goals in mind, in the end when we were afraid fighting in secrecy about who to trust and who we had to kill. Arguing over who would act as the new Lord Regent... And she listened, eyes wide. She's become an interesting girl, if she lives she'll make a memorable Empress. Go ahead, kill me or take me to Coldridge Prison... Make your choice, she'll be watching."

- Havelock to Corvo about Emily and pretending to hand over the key to the room and allow Corvo to kill him.

Farley Havelock is the main antagonist of Dishonored. Formerly an admiral in the Gristol navy, he was discharged for refusing to sail under the command of the Lord Regent, Hiram Burrows. Although the official story is that Havelock was discharged from the navy after refusing to sail under Hiram Burrows, the Heart adds that he tried to seize control of the military after the Empress was murdered. Cecilia mentions to Corvo that the story isn't entirely clear.

Involvement
Some time after Empress Jessamine Kaldwin was assassinated and her daughter Emily kidnapped, Havelock organized the Loyalist Conspiracy. Since he had become the owner of the Hound Pits pub several years prior to the outbreak of the rat plague, he utilizes the drinking establishment as the Loyalists' base of operations. In his position as the leader of the conspiracy, Havelock arranges Corvo Attano's escape from Coldridge Prison with the help of Teague Martin, and tasks Corvo with completing various missions to achieve the conspiracy's ultimate goal of overthrowing the Lord Regent, and rescuing Emily.

Throughout the course of Dishonored, Havelock updates the log in his room at the Hound Pits pub, detailing his thoughts and feelings. In it, he praises Corvo for completing feats he had not thought possible (for instance, noting that he had given Corvo "odds of 1 in 5" of escaping Coldridge), while simultaneously express concern over Corvo's skill, and what threat he might pose to their future efforts.

After the fall of Hiram Burrows, Havelock, Martin, and Pendleton betray Corvo, poisoning him and leaving him for dead. The three conspirators kill many of the other Loyalists to cover up their connection to Corvo's actions and set the City Watch on the Hound Pits, purporting to have "discovered" the conspiracy's base of operations. They then take power by presenting the "rescued" Emily and ruling in her name, with Havelock himself becoming the new Lord Regent. Additionally, Havelock appoints himself Grand Admiral of the Fleet and Supreme Commander of the Combined Armies of the Empire. Havelock then retreats to Kingsparrow Island, along with Pendleton and Martin taking Emily with him.

Low Chaos
Havelock can be found in the penthouse of Burrows Lighthouse on Kingsparrow Island. Pendleton and Martin are dead at a table, apparently poisoned. Havelock is found muttering to himself about the failure of his plans and Corvo's imminent revenge, having succumbed to feelings of guilt and extreme paranoia.

Corvo must deal with Havelock to get the key to Emily's room. If confronted non-violently, Havelock will not attack Corvo, but will instead face a nearby fireplace and speak briefly before offering the key if Corvo takes the key Havelock will begin a duel to the death with Corvo in which he can possibly be killed. (Note that if Corvo listens to Havelock's full speech and then takes the key without harming him, Havelock will attack.) His non-lethal fate is unknown.

High Chaos
Havelock is found holding Emily hostage on the level above the penthouse, at the edge of an unguarded walkway over a fatal drop. If Corvo does not act or if he moves too close to Havelock, the Admiral will jump from the walkway to his death, taking Emily with him. If Corvo manages to approach Havelock before he can jump (Blink and Bend Time being popular methods), he can save Emily, and Havelock will fall to his death alone. If Corvo kills Havelock with a ranged attack or power, Havelock will fall but Emily will grab the edge of the platform. Corvo can then pull her up. It is also possible to deal with Havelock non-lethally in the High Chaos ending; simply possess him and walk him away from the edge, and then choke him out.

Trivia

 * The twist that Farley Havelock is the main antagonist bears many similarities with Sentinel Prime from Transformers: Dark of the Moon and Prince Hans from Frozen, as all three are introduced as supporting characters of their respective story and are revealed to be the main villain and later betrayed the protagonists for their selfish desires and borrowed the minions of another villain and trying to take over a certain place.
 * Havelock seems to admire Corvo as he compliments his skill throughout the course of the game, telling Corvo that in one night he'd done more than most men do in a lifetime or doubting a dozen soldiers could have done better after capturing Sokolov. In the final mission on low chaos Havelock will be disappointed in himself and say that he's going to lose everything to a man better than he is should Corvo choose to non-lethally deal with his targets.
 * Developer Harvey Smith confirmed that Havelock was in his fifties.
 * It is impossible to beat Havelock in a blade lock, even with the upgraded sword and fencer bone charm active, it's unknown why this occurs it is possible that it was added to increase difficulty against him or that Havelock is physically stronger than Corvo.
 * Havelock is aware of Corvo's powers and will not be surprised by Blink when fighting him unlike other hostiles besides Daud.