Emile Danko is the the primary antagonist of Volume Four. He is the lead hunter for the government operation to round up evolved humans, which is headed by Senator Nathan Petrelli until Danko seizes control of the operation later in the volume.
Danko was first introduced when he took down Tracy Strauss in her house at the beginning of volume four. He is working with Nathan Petrelli and Noah Bennet in a government operation to round up people with powers. Danko views evolved humans as monsters, as opposed to Nathan, who reminds Danko that they are people, not monsters. Nevertheless, Danko's views remain unchanged. In Trust and Blood, he has an argument with Nathan wherein Nathan wants to safely quarantine people with powers until they can find a way to remove their special abilities but Danko wants to kill them.
Danko is also in conflict with Nathan and Noah, viewing them both as compromised, because of their protection of their daughter, Claire, whom Nathan has ordered immunity for and granted her a free pass from this operation. In addition to Noah and Nathan's protection of Claire, Danko also disapproves of Noah and Nathan's partiality to Nathan's brother, Peter, another evolved human.
When the operation is in danger of being dropped by the government, Danko loosens Tracy's chains in an effort to continue the operation, leading to her escape which results in the murder of an employee in front of a government official. Upon witnessing the employee's murder at the hands of Tracy's powers, the government allows the operation to continue, allowing Danko to continue his work of taking people down with special abilities. Peter uses the information he gains from Matt reading Noah's mind to find Danko with intent to kill him. Peter holds a gun to Danko's head, but Nathan saves Danko. In Exposed, Danko tracks Peter down and is about to kill him, but shoots him in the arm. Peter is saved when he is flown away by his brother, Nathan, unseen by Danko.
Danko's hostile relationship with Nathan comes to a head when Nathan manages to remove him from the operation and replaces him with Noah. Danko pushes Nathan out a window, forcing Nathan to expose his own ability (flight). Nathan, realizing this means the end of the free pass he had given to his daughter, flies to save Claire and protect her from Danko/the operation by hiding her in Mexico while Danko seizes control of the operation. Now unfettered, Danko ruthlessly hunts evolved humans and teams up with Sylar. Angela Petrelli and Noah covertly work together to overthrow Danko.
During volume five, Danko is chopped up and killed in Orientation by Edgar. Later, Noah comes and finds a key in Danko's split open stomach, which opens a box that contains a compass. Edgar returns and Peter fights him and Edgar runs off, without the compass he came for.