Lee

Series 1
Lee is first seen in S01E01 with Arby when they enter Doomsday Comics as they search for the Utopia Manuscript and the location of Jessica Hyde. He enters ahead of Arby and kills a shopper with a lead pipe before beckoning the second man over and killing him with his portable gas canister. When Arby obtains Bejan Chervo's address, Lee uses his gas canister to kill the remaining man. He disconnects the gas and leaves for a cigarette.

Arby and Lee arrive at Bejan's address and while Arby holds Bejan hostage and questions him on the whereabouts of Jessica Hyde, L

ee finds the manuscript and places it in their bag before watching Arby push him to his death over the balcony. Grant Leetham, who had snuck into Bejan's apartment witnessed his murder and after stealing the manuscript, fled. Although he escaped, he scraped his arm on the door and Lee was able to take a DNA sample, with which they are able to learn Grant's identity. They wait for Grant outside his home, but unknowingly alert him of their presence when Arby opens their car window to let Lee's cigarette smoke out, and he begins coughing. When Grant stabs the man whose car he tried to steal, the duo notice Grant run. They then wait and ambush him at his school while posing as policemen, resulting in Grant escaping once again and going on the run from the Network. Afterward, Lee and Arby visit Wilson Wilson. Wilson is handcuffed to a chair and informed that Lee will, one after another, rub chilies, sand and bleach into his eyes before finally using a spoon for information on the manuscript and the whereabouts of Jessica Hyde. During the torture, Lee removes Wilson's eye and after Arby concludes he has no valuable information, leaves Lee to finish up. However, Lee desperately wants a cigarette and so leaves Wilson for a few minutes.

This smoke break gave Wilson enough time to dislocate his thumbs and escape from his handcuffs. Once Lee returned, he found Wilson waiting with a gun, albeit partially blind. When attempting to get close enough to get the gun, he almost manages but is shot in the lung by Wilson who escapes, believing to have killed him.

In S01E02, Lee is briefly seen in a flashback, strangling a comic book dealer to death while Arby obtained the address of Doomsday Comics, who purchased the manuscript from him.

Series 2
The gunshot wound did not kill Lee, but instead seriously wounded his lung and gave him nerve damage, which resulted in him losing the use of his left arm.

Lee is sent by the Network to find Arby to bring him back for an assassination job. Lee finds Arby, explaining his survival and why he's come to find him. Although Arby declines to help, Lee subtly threatens Tess and Amanda to ensure his compliance before bringing him to Milner.

Lee and Arby's arrival interrupts Wilson and Milner having a conversation, Wilson appearing terrified at the sight of Lee. Milner happily welcomes Arby before giving him his mission of killing Christian Donaldson and after he leaves, Lee approaches her and states that she's being “uncharacteristically soft”. Milner then instructs Lee to send a SWAT team to make sure Donaldson is dead. Just before he leaves, Lee gives Wilson a slight wink. Joe, Ian's boss, arrives at work, he finds Lee doing something to Ian's computer. When his policeman charade fails to work on Joe and he attempts to call the real police, Lee slits his throat with a Stanley knife and beats him over the head with a fire extinguisher, an act later blamed on Ian.

Lee encounters Wilson again, taunting him over his disfigurement and defending his actions against him as “Just doing my job.” Milner then arrives and tasks the two with finding Donaldson, who is on the run. While in their car, Lee annoys Wilson some more, stating his knowledge as useless and also revealing that it was he who killed his dad. When Lee figures out where Arby and the others are going, Wilson pickpockets Lee and steals his gun, prepared to kill him. Lee, unfazed, walks over to the car and removes a crowbar which he threatens Wilson with, telling him Milner likes him because he believes in The Network's cause, hinting that he may not. He smashes Wilson's knee and forces him to drop the gun. He then takes his gun back and tells Wilson, “It's not that you can't take life. I reckon you could take billions. But, it would have to be necessary. Killing me just… isn't necessary.” before leaving to find the others alone.

When he finds Ben's house, he discovers that he and his parents are already dead. Arby then appears and bargains for Tess and Amanda's safety in return for handing Donaldson over. When Arby provides Lee with a live feed of an unknown location -possibly in Albania- to ensure that Tess and Amanda are safe, Lee is allowed to kill Donaldson and then tries to convince Arby to hand the others over too, only to be met with the question of Jessica Hyde's whereabouts.

When Wilson realizes that Milner went missing at Dugdale's house, he finds Lee to have him accompany him there, only to be insulted and told that everything will be back to normal soon. While questioning Ian, Becky, Grant and Dugdale Ian reveals that he knows Milner is Mr. Rabbit. Lee fails to hear this and is sent outside by Wilson, although he protests, claiming he can be quite effective at attaining information and that he should know that more than anyone.

In a deleted scene, Lee visits Geoff, sizing him up and checking if he has any health conditions. When questioned, he explains that Geoff is getting the blackmail money but if he steps one toe out of line, then he'll come back and kill him before going and doing the same to his wife and children.

When Arby is comatose in hospital after being shot by Philip Carvel, Lee disguises himself and attempts to kill him, only to be halted by Jessica. During the interaction, Lee states that nothing scares him except for Arby but is forced to leave. When Leah determines that Terrence is the agent who will release the vaccine, she sends Lee to kill Michael Jones, one of the other agents trained to release it. When Terrence is killed and Wilson seizes power of The Network, he calls Lee into his office and prepares to kill him. Lee once again states that Wilson would need a reason to kill him before being shot in the head by him, proving that he is no longer Wilson Wilson and ending Lee's psychological taunting.

Trivia

 * The yellow suit that Lee dons throughout the entirety of the second season was designed by Topman specifically for the show.
 * Lee uses a vape in S2, while he was seen smoking in S1. He likely made the switch as a result of the lung damage he sustained after being shot by Wilson.