(Capcom's primary storyline)
"It's how you deal with hardships in life that makes you a man, Ethan!"
— Lucas to Ethan Winters in the Barn.
Lucas Baker (ルーカス・ベイカー Rūkasu Beikā ) was a resident of the Baker ranch, located in Dulvey, Louisiana. He was the son of Jack and Marguerite Baker, the older brother of Zoe Baker, and the nephew of Joe Baker.
Lucas was apparently a "bad seed", but despite his unruly ways, he was a gifted inventor and won several awards for his work which he displayed in his room. He also mentioned having gotten a jigsaw puzzle from his mom as a reward for going to the hospital for a head scan.
It can be presumed that he was already mentally unstable. He also chronicled the time when he trapped one of his childhood bullies, Oliver, in the attic and sealed it with a remote, leaving him to die of thirst and starvation. He then fused the remote with one of his trophies, disguising it as a lamp to prevent Zoe from getting into the attic. Later on, he went on to study at a university within the state of Louisiana.
By 2014, he and his sister were still living at their parents' house. His anti-social nature led him to constantly fall out and argue with his family, resulting in him creating a "Fuck You" list on his laptop to log these events and vent his frustrations. After a violent storm hit the surrounding area, Lucas went outside and found a shipwrecked tanker. Telling his father about it, they went to investigate but found only one survivor; Mia Winters. Lucas then brought Mia in.
Jack eventually returned with a girl named Eveline, as Lucas watched. He was irritated that Marguerite let Eveline have his old bedroom, although he nonetheless consented. After Eveline had woken up, Lucas wound up unconscious, and eventually was dragged by Jack to "meet Eveline" where she gave him her "gift", with him telling his father to not do it in sheer terror.
Meeting Eveline & the Connections
Eveline, who had the ability to produce a mold substance and control people she came into physical contact with, managed to take control of the Baker family, Lucas included, grooming them and Mia to become her ideal family. Along with his father and mother, Lucas gained regenerative abilities, even being able to grow back his hand after Jack cut it off. However, Lucas was met by agents working for The Connections, who provided him with a serum that stopped Eveline from controlling him. In exchange, Lucas spied on his family for them, whilst managing to fool Eveline into thinking he was still under her control. During his time of possession, Lucas also began building elaborate puzzles within the family's old barn, some of which were certain to cause the death of the victim, even when solved. He was also given the role of lead researcher by the Connections, much to the dismay of another researcher, who had a master's degree in microbiology from Stanford University. According to the researcher's note, he would commonly make test subjects fight each other and perform pointless autopsies. Aiming to take Eveline’s Mold for himself, Lucas eventually betrayed the Connections; arranging for all their researchers to be locked in a room to be killed by Molded.
After the Sewer Gators arrived in the Dulvey Haunted House and were confronted by Jack Baker, Lucas took Clancy Jarvis, the sole survivor, and forced him and Hoffman, another survivor, to play 21, a modified version of Black Jack of Lucas's design, where the loser would suffer painful consequences. Clancy soon proved himself to be the better card player between himself and Hoffman, leading the latter's eventful death. Lucas later put him into the "Party Room" within the re-purposed barn. After removing his bindings, he taunted Clancy into solving the puzzle, putting a candle on a cake, promising him freedom if he did. However, unknown to Clancy, Lucas had rigged the puzzle to require a winder, which would spill oil onto the floor. Completing the puzzle, the cake exploded and set fire to the room. Unable to extinguish the flames or escape, Clancy died as a result. Shortly after the flames died out, Lucas came into the room to retrieve the camera, taunting Clancy, even after his death.
Conflict with Ethan
"Goddamn, old man, not again!"
— Lucas complains as Jack severs his arm.
When Ethan Winters, Mia's husband, was captured by his father, Lucas attended "dinner" with his family to welcome him to their group, continually throwing food at him whilst he was unconscious. Eventually, Lucas threw his dinner plate at him, to which Jack responded by slicing off Lucas' hand, causing the latter to shout "not again!", signifying that this wasn't the first time it had happened. When a police officer arrived and knocked at the door, Lucas and Jack disappeared, possibly to either hide from or murder him.
Whilst Ethan was investigating the old family house, he found Mia in the basement. However, before he could find a way to her, Lucas appeared behind her and took her hostage. During Ethan's investigation of the old house and fight with Marguerite, Lucas placed keycards around the family's house and the key to access these rooms within the neck of the now deceased deputy. He later captured Zoe in the family trailer as she retrieved an ingredient to a cure for Eveline's mold, leaving the severed molded head of the officer in the fridge with a note attached to it, reading "the pig is in the dissection room, bitch!". As Ethan arrived at the trailer after collecting the ingredient, Lucas called its phone and, when Ethan answered it, taunted him, telling him about his capture of Zoe and sending him to collect key cards that would allow him access to the barn. Lucas also filmed a short video, explaining to Ethan how he wants things to stay the way they are, setting a television up to play it.
As Ethan progressed through the barn, foiling his traps and defeating the Molded, Lucas would continually mock and tease him, getting on his nerves. Once he made it to the Party room, Ethan, having seen Clancy’s fate on a videotape and learning from his mistakes, completed the puzzle without releasing the oil. Angered, Lucas threw a stick of dynamite through a hole in the room's wall to kill Ethan, only for the latter to throw it back through the hole, enabling his escape. Furious at this twist of events, Lucas fled. He taunted him one last time via video recording, suggesting that he had more surprises in store for Ethan, although he was not seen again afterward. However, his IED traps are encountered when Ethan later entered the salt mines. Blue Umbrella's special forces team survey the Baker Ranch and Chris Redfield reports that Lucas was in the salt mines and that he was going to look for him. After helping Ethan kill Eveline, Chris entered the salt mines in pursuit of Lucas.
Operation Lurking Fear
"Oh I've got something for you— you're fucking screwed!"
— Lucas during his mutation.
At an undisclosed point in time, Lucas betrayed the Connections scientists working with him, feeding them all to the Molded before covering the incident up as an accident. With Umbrella in hot pursuit and a third party in need of the E-Series data, Lucas commenced a final effort to complete his transactions and cut ties with his former business partners. He captured three Umbrella soldiers working under Chris in order to use them as bait. When Chris attempted to save the first of these captured operatives, Lucas, under the guise of another operative, attached a plastic explosive to Chris's arm before detonating a similar bomb on his hostage's neck. Lucas proceeded to release E-Type spores throughout the mines as a further means of trying to kill Chris. He later decapitated the second captive soldier with a buzz saw and blew the final operative's head off with another remote bomb. Mocking Chris, he then activated the bomb he had placed on his arm, although Chris was able to remove it in time by freezing it with liquid nitrogen.
In an effort to finally kill Chris, Lucas causes the salt mine to self-destruct, then sends an email containing research data about Eveline and the Mold to an unknown client. However, Chris manages to survive the explosions in the mine and proceeds to continue chasing Lucas. At the end of the chase, Lucas ambushes Chris with a knife, but is pushed back and shot in the chest by him, triggering both Lucas's grotesque mutation and his final fight with Chris. Chris eventually gains the upper hand, incapacitating Lucas by fatally damaging him, and then permanently killing Lucas by shooting him in the head with his shotgun. Chris then shoots out Lucas’s computer, preventing the unknown clients from receiving his data.
Mutated Lucas is encountered as the ending boss fight of the "Not A Hero" scenario. He will start the fight by falling from the lump in the ceiling. He is invulnerable during the initial recovery animation and when he roars. Lucas' head is the only weak spot that he has. The player must continually shoot it until he reaches his damage threshold and goes into a state of shock. During this state of shock, his chest weak spot is exposed, enabling the player to do increased damage to him. Inflicting the damage equivalent to 5-6 RAMROD shots on his chest should be enough to put him into his second phase, where he will jump on top of the structure in the middle of the room. He will start to complain about head trauma and will undergo additional mutations to his arms as well as envelop the entire room in spores that will drain Chris' oxygen tank. The only way to regain oxygen is by using the 2 oxygen tanks that are mounted on the wall. They will be lit with a green light. The same process must be repeated, shoot his head until he goes into a state of shock, then shoot his chest. Incendiary grenades are a guaranteed stun so long as he is not in any kind of flinch animation. If Lucas is deflected, he will be stunned for a few seconds, providing a window to inflict damage.
- If close to the player, Lucas will do a vertical slam, a horizontal strike with his right tentacle, a slow jab with his left hand, a backhand with his left hand that enables him to back up, or a grab which is an instant kill, unless you block or deflect it. All of these attacks can be deflected. The horizontal strike can be crouched under and when the grab is deflected, it will cue a cutscene that will cause Lucas to immediately be put into a state of shock.
- If at mid-range, he will do a jump attack where he will spin his right hand and jump. He can sometimes do it at close range. The player must try to sprint to either the left or the right or be ready to get behind cover when it happens. The jump attack cannot be deflected.
- If at mid-range, he can do a 3 or 4 hit combo and swap between his left and right-hand attacks while moving toward the player. Keep your distance or try to deflect an attack to stop the combo. Bear in mind, he can sometimes chain his instant kill grab into the combo.
- Sometimes, when Lucas jumps down from the structure in the middle of the room, if you are too close to him, he will immediately start an attack upon landing.
- During the second phase, he can fire a stream of acid from his left hand. Either get behind cover or get close to him and crouch.