Dad

James, also known as Dad, is the father of the Lone Wanderer and Vault 101's physician

Project Purity
Before the Lone Wanderer was born, James led an ambitious scientific endeavor known as Project Purity. He and his group of scientists, including wife Catherine and Dr. Madison Li, aimed to build an advanced water purifier within the ruins of the Jefferson Memorial, which would serve to purify the water of the Potomac.

Under the protection of the Brotherhood of Steel, research was well underway when Catherine and James discovered they were expecting a child. Catherine was determined to finish the project before welcoming their child, spending all day in the lab and refusing to rest despite James' objections. The project began to lose momentum, lacking concrete results while having to compensate for lost time due to super mutant attacks. The number of mutants was steadily increasing, and protecting the project was becoming increasingly difficult for the Brotherhood. After losing two members with three injured in one week, the relationship between the chapter and the scientists began to strain.

Before the project could reach fruition, Catherine delivered their child but passed away due to complications of childbirth. Distraught, James weighed his options, recognizing the lack of progress on the project, alongside several super mutant attacks per day, and continued challenges working with the Brotherhood. He decided that regardless of how much the project meant to him and to Catherine, the location was not safe for an infant, choosing instead to leave the project, putting the needs of his child before his own.

Vault 101
Escorted by the Brotherhood's Star Paladin Cross, James pressed onward with his child, traveling across the D.C. ruins to Vault 101. Along the way, James and Cross also stayed at the saloon in Megaton owned by Colin Moriarty briefly.

After successfully reaching and entering the large underground vault, James began his service as the vault's physician. Soon after he took up residence, his research into Project Purity began again, this time consisting of sneaking into the restricted areas of the vault each night, searching for anything relevant or helpful towards the project aims. Amidst advanced technology, James sought any information within the Vault-Tec facility that could potentially prove useful. Having no luck, he broke into the overseer's office and hacked the terminal, gaining access to restricted files. James found a promising lead by way of information regarding prominent researcher and technological genius Dr. Stanislaus Braun. James learned of Braun's involvement in a social preservation program, and his research into a piece of technology called a GECK, or Garden of Eden Creation Kit.

The information regarding this piece of technology was completely foreign to James, who mentioned that it seemed as if it were nothing short of a miracle. The device was a terra-forming module, capable of producing life from within a barren ecosystem. He was skeptical of such a device being a reality, expressing that the entire idea sounded like pure fantasy, even for someone of Braun's capabilities. He learned that not only did it exist, it was distributed to several vaults to be used after an atomic war. James discovered that Braun had secured a place in Vault 112, considering the possibility that Braun's research information could be held within, surmising that if he could gain access to only a fraction of Braun's genius, Project Purity could become a reality.

Years passed and James continued to serve as the vault's physician, all the while caring for their child as they progressed through each stage of their child and young adulthood. The lingering drive to move forward on Project Purity never left James' sight, however, and he was confident that Braun's research may serve as Project Purity's missing puzzle piece. The Lone Wanderer having reached the self sufficiency of teenage years, James decided to attempt an escape from the locked down facility. In the interest of his child's continued safety, he intended to have them remain behind in the vault, unware of his plans or destination.

Capital Wasteland
The act of leaving the vault caused a crisis within, and the overseer considered the Lone Wanderer complicit in their father's plans. Forced to flee from the hostile security forces, James' child also escaped from the confines of Vault 101, intent on following him to Braun's vault. James made his way to Megaton, Galaxy News Radio, and then the GNR building plaza, meeting with old acquaintances Colin Moriarty and Three Dog along the way. His old friends encouraged him onwards, and he decided that he would need Dr. Madison Li to join the project once more if he hoped to see it through.

James tracked Madison's whereabouts to Rivet City, and approached her with a request to join forces once again. However, it had been nearly 20 years since Madison and James had worked side by side on Project Purity, and unable to reconcile what had happened previously, she declined.

Vault 112
Undeterred, James traversed to Vault 112 in hopes of tracking down Braun or his research. There was still a study being undertaken, but it was not what James anticipated. Braun was engaged in research revolving around the oversight of several families trapped in virtual reality pods in a simulation entitled Tranquility Lane. James, unaware of these plans, became ensnared in Braun's trap as well. Braun turned James into a dog for the purposes of the sim, therefore unable to communicate with anyone else present in a recognizable way.

Having been trailed by his child, they were able to follow him into the simulation, become part of the test, and successfully break the two of them free from its trap. James was unaware that his child was even able to leave, let alone find him and free him. James took a moment to express his feelings on the events having transpired recently, speaking briefly with his child before agreeing to meet up in Rivet City. Despite the experience, James had acquired the research information he sought, and armed with this last crucial element, agreed to meet up with the Lone Wanderer in Rivet City in an attempt to recruit Dr. Li.

As James had hoped, information about the GECK was enough to convince Madison of the project's continued viability. Madison brought her research team along to the memorial and the group commenced work on Project Purity after nearly 20 years.

Enclave interference
Shortly after James and Madison began work once more on the project, a large Enclave force arrived at the Jefferson Memorial. Soldiers under the command of Colonel Autumn stormed the activation room where the scientists were working. Autumn declared the Enclave was taking over the project and demanded James turn over all materials related to this project. James assured the colonel that the facility is not operational and never has been, in taking over it would be a waste of their efforts.

Autumn, losing patience, executes one of the scientists, Janice, and repeats his demands of James, for him to immediately hand over all materials related to this project, and aid the Enclave in making the purifier operational at once.Colonel Autumn: "By the authority of the President, this facility is now under United States government control. The person in charge is to step forward immediately, and turn over all materials related to this project." James: "That's quite impossible. This is a private project; the Enclave has no authority here. I'm going to have to ask you to leave at once." Autumn: "Am I to assume, sir, that you are in charge?" James: "Yes, I'm responsible for this project." Autumn: "Then I repeat, sir, that you are hereby instructed to immediately hand over all materials related to the purifier." James: "I'm sorry, but that's...." Autumn: "Furthermore, you are to assist Enclave scientists in assuming control of the administration and operation of this facility at once." James: "Colonel... Is it Colonel? I'm sorry, but the facility is not operational. It never has been. I'm afraid you're wasting your time here." Autumn: "Sir, this is the last time I am going to repeat myself. Stand down at once, and turn over control of this facility." James: "Colonel, I assure you that this facility will not function. We have never been able to successfully replicate test results..." Autumn: "I suggest you comply immediately, sir, in order to prevent any more incidents. Are we clear?" James: "Yes, Colonel. I'll do whatever you want; there's no need for more violence." Autumn: "Then you will immediately hand over all materials related to this project, and aid us in making it operational at once." James: "Very well. Give me a few moments to bring the system online." James: "Nearly finished..." James: "...run... Run!..." (Autumn's and James' dialogue) James instead causes a radiation leak in the activation room, killing everyone except Autumn. James collapses and dies after telling his child to run.

Effects of player's actions
When the Lone Wanderer is doing tasks to make Project Purity work, James will say that he heard of their actions. His reaction changes, depending on the outcome of the quest The Power of the Atom. If the quest was not resolved at all, or if James is spoken to again after he comments on the aforementioned quest, he will instead comment on the Lone Wanderer's current Karma level.

Inventory

 * 1Only while in Vault 101.
 * 2On his way back to Rivet City.

Appearances
James appears in Fallout 3 and Fallout Shelter.

Behind the scenes

 * James is voiced by actor Liam Neeson, after whom the character is also physically modeled. Todd Howard stated that James' role "was written with Liam in mind and provides the dramatic tone for the entire game. Liam is absolutely amazing to work with." Neeson himself said that it has "been a pleasure bringing the father to life and working with the wonderfully talented people at Bethesda on Fallout 3," and that he hopes that "the fans of the franchise and the game will be excited by the results."
 * According to Emil Pagliarulo, the original script would have placed James in Vault 87, where he would have been turned into a super mutant. If encountered by the Lone Wanderer, he would have begged his child to end his life. The script was changed for several reasons.
 * In Fallout: New Vegas, a picture of James and Catherine can be found in Vault 21. According to Jason Fader, it was one of the things that "made it into the game that only few on the team truly understood."

Bugs

 * On the way back to Rivet City from Vault 112, he will sometimes get stuck while traveling with him. If this occurs, fast travel to Rivet City and wait 24 hours in the science lab. He will appear and start talking to Doctor Li.
 * James might disappear if you fast travel to the Jefferson Memorial from Vault 112.
 * If the player glitches into the Citadel and completes the quests Finding the Garden of Eden and The American Dream, they can still go to Smith Casey's garage and take him to Rivet City. Upon arrival, he will state "give me a moment to speak with Madison." At this point, the quest Take it Back! is already started making him unkillable and the quest The Waters of Life will be impossible to complete.
 * James may not follow the player character to the Jefferson Memorial by fast traveling.