James (Poker Night)

A nameless masked serial killer who went by the alias "James" at one point was the main antagonist of the 2014 horror movie Poker Night (sold in some markets under the title The Joker).

He was portrayed by Michael Eklund who played Michael Foster in The Call.

History
Before becoming a serial killer, "James" was just a normal man with an ordinary family (a wife and a son) living an ordinary life and working an ordinary office job. After years of the same boring droning life, he eventually decided that he couldn't take being a sheep of society any longer and couldn't take the idea of his life meaning nothing. As such, he set two goals for himself:

Goal #1. Have Sex With Little Girls

Goal #2. Kill Anyone Who Gets In My Way

Deciding that he would be constrained by his family, James murdered his wife and child and set their house on fire with a cigarette and gasoline, and then in order to study the best ways of killing and raping and getting away with it, James first watched hundreds of documentaries on serial killers and rapists, before searching social media for advice.

Eventually James met the serial killer Terrence Alby online, and Terrence took James under his wing as his apprentice. Together, the pair would often meet up and visit childrens playgrounds to find victims to take home and rape and kill. They once even did this using an ice cream van, and often they drove around with a man dressed as a clown and a man dressed as a rabbit, while James wore a scarecrow-like mask.

After Terrence and James murdered James's parents, James finally felt like he had graduated from Terrence's leash, and decided to break it out on his own, murdering over forty innocent people through various methods, and stuffing their bodies (some cut to pieces) in a shipping container. Once James had filled the container, he called Terrence to show him his "masterpiece", only to find that a police officer named Stan Jeeter had broken into his container. Jeeter didn't see James, who watched helplessly as Jeeter unloaded his pistol into Terrence.

Devastated by the loss of his mentor, as well as the fact that Terrence was given credit for his crimes, James just didn't know what to do, and became depressed. Even his clown and rabbit friends could never bring him any young girls who could return him to his happy state, so he left them and decided to focus his efforts on utterly destroying Jeeter as a person by framing him for a kidnapping and double homicide that he [James] would commit.

Firstly, James spied on Jeeter for months and discovered that Jeeter was having an affair with Police Chief Maxwell's underage daughter Amy. James began photographing Amy obsessively, as well as the pair together, in order to frame Jeeter for having a dangerous obsession with Amy (he even found a way to photograph the pair having sex in Jeeter's police car). After some time, James kidnapped Amy and frequently drugged her, keeping her for 2 weeks.

After spotting Jeeter's car, James released Amy, who ran in front of Jeeter, forcing him to perform an emergency stop and chase after her. James then injected Jeeter with a knock-out drug and held him tied to a chair in a room next to where he was keeping Amy, all the while psychologically torturing Jeeter and giving hints about his past. At one point, he even tatooed a hyper-realistic drawing of Amy's face onto Jeeter's arm, to further add to the idea that police would get of Jeeter having been an obsessed psycho-stalker.

At one point, Jeeter tried to escape and find a phone to get backup to rescue Amy, and discovered that James had pictures of him and Amy all over a darkroom, as well as pictures of hundreds of other young girls who James had killed. A horrified Jeeter left the darkroom, and saw what he thought was James sat on a chair. When he attacked "James", he discovered that it was in fact the decapitated head of a random person sitting on top of some cushions. James then knocked out Jeeter and stuck his body to the wall of the bunker with superglue, before going into the next room and giving Amy an opportunity to call her father, alerting the police to his location. During the call, he raped Amy while her father listened in horror.

Chief Maxwell traced the call to James's house, and was quickly drugged by James and taken to his CCTV room. While in the room, James and Maxwell saw that Jeeter had freed himself from the wall and he and Amy were trying to escape. James saw this as an opportunity to get rid of Maxwell (who knew James's real face due to meeting him outside his house without his scarecrow mask) and to frame Jeeter for murder. James put a scarecrow mask onto Maxwell, and held him at gunpoint, while wearing gloves, and took him down to the basement, where Jeeter shot him using his gun (which the real James had left on the floor deliberately), while Amy (who realised that this was her dad) pleaded with him not to kill the man in front of them. Jeeter shot Maxwell dead, emptying his cartridge, after which the real James entered the room and removed Maxwell's mask, showing him that he had killed an innocent man (also his girlfriend's father) and that he had filmed the entire ordeal.

James then knocked Jeter out using a drug cocktail, and used a stronger cocktail to give Amy an overdose that put her in a coma.

Once Jeeter's partner Calabrese arrived at James's house, inverstigating Maxwell's disappearance, the pair enaged in a gunfight which concluded with Calabrese shooting James and restraining him using handcuffs by tying him to a radiator. James however was able to free himself from the cuffs, and shot Calabrase in the head whilst he tried to free Jeeter.

Eventually, Jeeter was able to escape and shoot James, before cuffing him to the same chain he had cuffed Jeeter to, before leaving the house and carrying Amy in his arms, only to be shot and arrested by the police, who believed that he (Jeeter) had been the one to murder Maxwell and Calabrese (especially given the mountain of evidence that James had placed incriminating Maxwell and making him look like a psychotic obsessed stalker). James quickly utilised his escapology skills to escape the cuffs, and chained up Calabrese's body in his place, leaving Jeeter as the only suspect for his crimes while he got away.

After several months, Amy eventually awoke from her coma and testified that Jeeter was innocent, leading to him being released from prison, and beginning his vendetta against James. Jeeter's investigation eventually led him to find James's lair and rescue a girl he had captive, before shooting the masked man who he believed to be James dead. However, as Jeeter removed "James's" mask, he saw that the man underneath had his mouth taped shut, and had a gun superglued to the inside of his hand.

Jeeter had killed an innocent man, and James was free to keep on living and keep on killing.

Trivia

 * James's true name is unknown, and it is unclear if the backstory he gave Jeeter is actually true or just a made-up story.
 * Despite the film's alternate title "The Joker", James does not at any point actually use this alias, and his mask itself more closely resembles that of Scarecrow than it does any other character. In fact, James doesn't seem to call himself by any alias as a serial killer, and doesn't have any kind of media nickname given to him.