The world is in pretty bad shape in the Fallout universe. People eke out an existence the best they can amidst the shattered remains of the United States. Everything revolves around survival and some individuals prove better at it than others. Thus, many of these hardy NPCs can be spotted across multiple titles.
It's worth noting that all of the games set between Fallout 2 and Fallout 4 take place within the same forty-six year period. As such, it's not uncommon to find some familiar faces wandering about the wasteland. Whether it's New Vegas, The Commonwealth, or the Capital Wasteland players are bound to run into somebody they have met before.
10 MacCready
In Fallout 3 the Lone Wanderer first encounters MacCready in Little Lamplight, a settlement composed entirely of children. The foulmouthed youngster is the self-appointed mayor of the community. He looks out for the other children, protecting them from malicious adults, or "mungos," as he says.
Ten years later MacCready can be found as an adult in Fallout 4 working in The Commonwealth as a mercenary. The Sole Survivor has the option of recruiting him as a companion once the player helps him clear up some business with the Gunners. Raising MacCready's disposition will get him to open up about his tragic backstory.
9 Harold
Harold's unfortunate tale spans three main entries in the series. Turned into a ghoul after his exposure to the FEV Harold can be met for the first time by The Vault Dweller in the original Fallout. By the time of Fallout 2 he can be met again by the The Chosen One as part of a side quest.
His fortunes take a turn for the worse by the time the Lone Wanderer is introduced to him in Fallout 3. A mutation growing within him eventually roots Harold to the ground and transforms him into a tree. A cult, mistaking him for a god, establishes a religion in his honor despite his pleas and protestations to the contrary.
8 Marcus
A hulking Super Mutant from Broken Hills, Marcus is a recruitable companion in Fallout 2. His specialty is in the use of big guns where he can be utilized as a tank-like character by the player. After the conclusion of the main quest Marcus parts ways with the Chosen One.
Nevertheless, Marcus appears yet again in 2281 during the time of Fallout: New Vegas. He helps run Jacobstown, a small community composed of other Super Mutants and Nightkin. The Courier can decide whether or not to help Marcus protect the town from the threat of encroaching mercenaries.
7 The Mysterious Stranger
A very unique character, the Mysterious Stranger has appeared in every main Fallout title in the series, including Fallout 76. His purpose is to defend the protagonist when a situation becomes a bit too dire. However, the appropriate perk must be unlocked first to make use of his help.
The Mysterious Stranger is recognizable due to his consistent outward appearance, which has changed little throughout the years. He typically sports a brown trenchcoat, fedora, and wields a pistol. Not a bad guy to keep around when things get a little heated.
6 Madison Li
Dr. Madison Li plays a significant role in two separate titles. In Fallout 3, she is an old friend of the Lone Wanderer's father and one of leading scientists of Project Purity. She acts as an ally to the player in the main quest to cleanse the waters of the Capital Wasteland.
She reappears ten years later in The Commonwealth as a member of the Institute. If the player decides to join that faction Dr. Li becomes a frequent contact and quest-giver. Otherwise, if the Sole Survivor allies with the Brotherhood of Steel, she can be convinced to switch sides and leave the Institute behind.
5 Arthur Maxson
Arthur Maxson holds a pretty distinguished lineage in the world of Fallout. As a descendant of the founder of the Brotherhood of Steel, a lot of high expectations define Arthur's life. His tutelage as a child under Elder Lyons can be witnessed in Fallout 3.
Maxson makes a dramatic entrance midway through Fallout 4's main quest aboard the Prydwen. Now commanding the Brotherhood of Steel forces on the east coast he seeks to bring The Commonwealth under his influence. Along the way Maxson clashes with the forces of the Institute, leaving the player to decide which faction to support in the end.
4 Tandi
For the New California Republic Tandi is a highly revered character. Elected as the second President of the NCR she led the fledgling republic through a period of internal prosperity and expansion. Two protagonists can meet Tandi at different stages of her life.
In Fallout the Vault Dweller is tasked with rescuing a sixteen-year-old Tandi from a band of Great Khans. Decades later the Chosen One encounters a much older Tandi in Fallout 2. She asks the player to negotiate with a group of settlers in order to bring them into the NCR fold.
3 Dr. Henry
A genetic research scientist, Henry is a former member of the Enclave. His medical clinic can be found in NCR town in Fallout 2. He offers a side quest to the Chosen One to test an experimental serum on a dangerous Super Mutant.
Forty years later Dr. Henry is operating a new clinic in Fallout: New Vegas. He is involved in several side quests that range from repairing Rex's cyberbrain to acquiring testing materials for his scientific experiments. Dr. Henry is also one of the former members of the Enclave that needs to be collected for the Arcade Gannon companion quest.
2 Liberty Prime
Most Fallout games feature the Brotherhood of Steel as a faction. They also tend to feature heavily in the main quests. A good deal of their ideology is centered around the preservation of pre-war technology. Liberty Prime, a massive war robot belonging to the defunct U.S. Army, is one such example.
The hulking monstrosity gives the Brotherhood a massive edge in combat. Once rebuilt in Fallout 3 it shreds through the Enclave soldiers like a hot knife through butter. His activation (or destruction) is left up to the Sole Survivor in Fallout 4.
1 Dogmeat
This loyal canine is quite possibly the most recognizable companion in the Fallout franchise. Dogmeat has made appearances in every main entry in the series and always as a recruitable companion. Although perhaps not the same dog in every game the character itself has been an enduring fixture of the series since the beginning.
In the original Fallout Dogmeat can be found in Junktown. He can be found again in Fallout 2 in the Cafe of Broken Dreams. The Lone Wanderer comes across the ubiquitous dog in a junkyard in the Capital Wasteland fighting off some raiders. Finally, the Sole Survivor can meet the German Shepherd shortly after emerging from Vault 111.