Rockstar Games has often placed Easter eggs in its games that reference its other works, but these have always been for fans rather than hints towards an interconnected universe. That is, until now. There is a theory going around that Grand Theft Auto V and Red Dead Redemption 2 do in fact take place in the same universe at different times.
While the games take place 114 years apart, with GTA V taking place in 2013 and Red Dead Redemption 2 being set in 1899, they could be connected through the time traveler. Many players probably missed out on this interesting character. The quest “Geology For Beginners” is easy to overlook, and while many may have run into Francis Sinclair, the quest giver, they likely didn’t complete the quest.
Sinclair sends players on a scavenger hunt across the map looking for rock carvings. He asks players to return to his cabin, just North of Strawberry, when they have found and recorded all the rock carvings. Even with online tutorials, it could take players hours to collect all 10 of the carvings, which is why many players don’t end up finishing the mission.
While the mission might be easy to forget, Francis Sinclair is not. He is one of the only red-haired characters in the game, the others being Molly and Sean. Hair isn't Sinclair's only distinguishing characteristic; he also has a large birthmark over his right eye.
While the game never explicitly claims that Sinclair is a time traveler and you meet him as a baby later in the game, it is heavily implied. Sinclair speaks like someone from the 1930s, using words like "hooch" and "jazzed," thoroughly confusing Arthur when they meet. Then there is the question of what the rock carvings mean and how they got there. Rock carving is an ancient type of art, but almost every carving found shows something that would be futuristic for the Wild West.
If a player does end up finding all the carvings, they can go back to Sinclair’s cabin to find out he’s not there. Upon entering the cabin, the player is met by a giant drawing of Sinclair with futuristic pictographs surrounding him. A woman returns during the cut-scene with a small red-haired baby named Francis. It seems that the first time the player meets Francis he is a lot older than he should be, as he is time traveling.
This could just be a cool mystery in the game, like the UFO on Mount Shann, but it also could connect to GTA V. While that game doesn't feature a Francis Sinclair, there is a mention of someone who looks striking similar to him. The Epsilon Program is a cult in the world of GTA that believes in many strange things. It's mentioned in GTA IV, but it's much bigger in GTA V.
According to its followers, the world is exactly 157 years old, dinosaurs are a lie and everyone is related except for red-haired people. Additionally, the believers of the Epsilon Program believe that people with birthmarks may be related to Kraff, the famous Emperor of the Fourth Paradigm. Both of these are features that Francis Sinclair possesses.
When going to the Epsilon Program's website, players will be met with examples of people who are supposedly descended from Kraff. One of these shows a person with a large birthmark is directly over their right eye. This has lead to speculation that Francis Sinclair is related to the famous Emperor Kraff, an alien from the GTA universe, as his red hair and birthmark perfectly fit the Epsilon Program's description. This would also help explain Sinclair's strange behavior in Red Dead Redemption 2, including his time traveling abilities, his speech patterns and even the UFO sightings.