(Capcom's primary storyline)
"Welcome to the family, son!"
— Jack Baker to Ethan Winters
Jack Baker (ジャック・ベイカー Jakku Beikā ) was the patriarch of the Baker family of Dulvey, Louisiana. He was the husband of Marguerite Baker and father to Zoe and Lucas Baker. He was the younger brother of Joe Baker. He and his family were behind a series of kidnappings and murders from 2015–2017, due to the control of Eveline.
As a child, Jack often fought with his older brother Joe, who boasted of breaking his nose and clothes-lining him in the swamp.
At a later point in his life, Jack served in the United States Marine Corps. He also became the owner of a 19th-century ranch in the Louisiana countryside, possibly handed down to him by his family, married Marguerite Baker and sired two children, Lucas and Zoe.
In October 2014, Jack thought of reinforcing the family ranch with Lucas' help in response to local weather forecasts predicting a hurricane. The resulting storm destroyed their old house and crashed a tanker into the nearby bayou. Lucas discovered the ship and informed his father, who decided to investigate it the next day.
Amongst the wreckage, Jack first found Mia Winters whom he housed in his daughter Zoe's trailer, and later a young girl named Eveline whom he took back with him to the main house to rest in his son Lucas' old room - completely unaware that the little girl was in fact an advanced human bio-weapon and that Mia was her escort. Jack left Eveline in Zoe's care while he went to check the state of the boathouse, but once Eveline woke and the power went out, he quickly came back only to find his wife Marguerite attacking Zoe in the bathroom. This forced him to restrain Marguerite and order Zoe to grab some rope from the garage, but by the time Zoe returned, the infection had taken hold of Jack as well as he attempted to drown Marguerite in the bath water. As an act of "devotion" to Eveline, Jack cut his chest open before proceeding to chase Zoe through the house, and although his daughter managed to escape his grasp, his son Lucas was not as fortunate as Jack dragged him into his old room to "meet" Eveline.
Under Eveline's control
Eveline's infectious Mold caused Jack and his family (except for Zoe) to go completely insane and eventually withdraw from community life altogether, leading the local parish to declare them dead. However, occasional sightings of the Bakers over the next few years led to rumors that the residence was haunted.
As Eveline became more obsessed with expanding her family, the Bakers began to abduct tourists and homeless people. Jack was responsible for killing, dissecting, and skinning the victims, whose bodies became the Molded, while Marguerite used their organs as a source of food. When Zoe attempted to communicate with the victims and help them escape, Jack and the rest of the family disowned her.
After foiling one of the escape attempts of sole surviving Sewer Gators crew member Clancy Jarvis, Jack locked him up in the basement so he could "meet some friends of his", referring to the Molded. However, once a few hours had passed and Jack realised that Clancy would not be defeated so easily, he personally confronted him at around 5 AM, but was defeated.
Jack briefly interacted with Marguerite while she traveled to and from one of the bedrooms to "care" for a captured Clancy. He briefly argued with Marguerite, incensing her so much that she burst into Clancy's bedroom and repeatedly stabbed him. However, Jack stopped her before she could deal a lethal blow by apologizing and reassuring her that he loved her.
The following month, Mia's husband Ethan Winters arrived at the house in search of his wife. Immediately upon his arrival, Jack began to silently stalk him from a distance, only closing in to try and recapture Mia after Ethan had freed her. Once Mia became possessed, he returned to the shadows to let her deal with Ethan, but after she was defeated he took matters into his own hands by sneaking up on Ethan and knocking him out, dragging both of their bodies to the main house. Jack tied up Ethan at the dinner table intending for him to join in on the family's feast of meat and organs from various human victims, which was one of several methods the family used to turn their victims into Molded. When Ethan refused to eat and Marguerite angrily stormed out of the room in response, Jack spitefully began cutting his face with a sharp kitchen knife, but was interrupted by the arrival of Deputy Sheriff Anderson and subsequently left to deal with the officer. Jack soon ran into Ethan after he successfully escaped his bonds, but soon lost him under the floorboards.
Jack left Ethan to his own devices for a moment, letting him meet with Anderson and rendezvous in the garage before trapping and ambushing them, immediately executing the deputy by splitting his head in two from behind with a shovel and then proceeding to brawl with Ethan. Jack ended up using Ethan's own car against him, driving into walls and wreckage until the vehicle began to burn, and fought through being burned alive before the car exploded and stunned him. Just as Ethan was about to leave via a ladder to the rafters, Jack grabbed his arm and told him he was going to "see something wonderful" before inserting Ethan's handgun into his mouth and blowing his own face off.
Second encounter with Ethan
Jack reawakened soon after Ethan made it into the main hall and surprised him in the bathroom, his head injuries visibly healing themselves, whereafter he stalked him throughout the house. He ended up following Ethan into the basement, where he managed to claim one of the dog reliefs Ethan needed to get out of the house, all the while muttering to the decapitated corpse of the deputy about his worries that Ethan will replace him as Eveline's "father" and saying that the deputy will help him (presumedly through mutation into a Molded).
Jack left the relief hanging on a hook in the drawing room as bait for Ethan, and this allowed the opportunity to knock him down into a small arena, forcing another duel from the pair with Jack using a custom made chainsaw-shears combo weapon. Despite this, Ethan still got the better of him and damaged him to the point where his upper body violently exploded, leaving only his legs intact to walk and fall towards Ethan.
Final battle with Ethan
The loss of his upper body triggered a mutation which led to Jack increasing multiple scores in size and his speech becoming much more demonic and strained, transforming into a reptile-like monstrosity which sported several eyeballs and was completely covered in Eveline's black essence. He confronted Ethan in the boat house during his rescue of Mia and Zoe, grabbing him and throwing him across the shack while rambling about how Ethan turned his own family against him and lamenting the death of his wife Marguerite. Jack was incapacitated by Ethan taking out his many eyes, but this did not keep him down which forced Ethan to use one of the serums he gained on Jack, rapidly calcifying him and thus ending their feud.
During Ethan's imprisonment within the Mold, Jack appeared to him in a vision, now free of Eveline's control. He expressed deep remorse for his actions, revealing to Ethan that his family were corrupted by Eveline and did not really wish to harm anyone before begging Ethan to free his family from her.
End of Zoe
The mutated Jack managed to survive Zoe's cure due to his poisoned cells growing out of control, evolving into a decayed but near invincible creature nicknamed the "Swamp Man" who acted on his own accord after Eveline's death. His new mission was to capture the now calcified Zoe, but his estranged brother Joe Baker managed to get to her first and take her to his shack. While Joe left the shack to find a cure for Zoe, Jack set the shack on fire and viciously murdered the Blue Umbrella soldier captive there in his attempt to kidnap his daughter - however, Joe is able to rescue Zoe and escape in a boat, completely unaware that the monster was in fact his own brother.
Jack managed to catch up with Joe at the Umbrella camp and attempted to take him on, but Joe escaped from his grasp and moved on towards an old paddle boat where the synthesizer for the cure was being held. Just as Joe managed to craft the full cure for Zoe, Jack jumped him and slammed him through the floor, engaging with him in close quarters combat, but Joe was able to best him by twisting his head clean off.
It wasn't long before Jack regenerated and once again caught up with Joe though, as he kidnapped Zoe right before Joe was able to administer the cure, carrying her into the Umbrella-quarantined zone and vanishing in the fog before Joe could pursue. Jack then sets up a trap for Joe in a derelict church, setting Zoe out in the open so he could ambush from behind. Joe got the chance to peel Jack's mask of mold back to reveal the remains of his face, and was so shocked at the Swamp Man's identity that Jack knocked him out and stuck him into a coffin which was then pushed into the depths of the swamp.
Jack has one final encounter with Joe in the main hall of the main house at the Baker ranch, where he had set up Zoe at a table. However, Joe was finally able to stop Jack thanks to his AMG-78 gauntlet completely obliterating his upper body, finally killing him and ending his misery