Red Dead Redemption and Grand Theft Auto are arguably the most popular and defining franchises that come under the Rockstar name. With both franchises rigorously adhering to the third-person and open-world Rockstar formula, the games are inherently similar in many ways.
However, putting core gameplay aside, there is one element of the two massively popular series' that has always fascinated fans and bred mass amounts of discussion and theories over the years. Despite taking place in different eras, it is very plausible that Red Dead Redemption and Grand Theft Auto actually share a timeline, and there is quite a bit of evidence to substantiate the theories that suggest this.
Grand Theft Auto 5: Jack Marston's Book
One of the most direct and overt theories that link both Red Dead and Grand Theft Auto comes with the wildly successful Grand Theft Auto 5. Throughout the game, there is a book that can be found on different shelves in numerous locations that conveys an extremely clear link between both franchises.
The book is titled "Red Dead," with the authorship given to a J. Marston. Of course, many may assume that this is a throwaway reference to John Marston, the iconic protagonist of the first Red Dead Redemption, however the theory developed by fans is slightly more intricate. Within the Red Dead franchise, John has a son called Jack, with the theory attributing the authorship to Jack, who may have written a book about growing up among the Van Der Linde gang, as well as the exploits of his father.
In both Red Dead and its sequel, Jack is shown to be a keen learner and avid reader with a passion for writing, further lending credence to the theory that he wrote the book in question. With the theory suggesting that this book became a famous staple of Old West literature, it is clear to see why this theory is so popular.
Red Dead Redemption 2: The Epsilon Program
A memorable side-plot in the story of Grand Theft Auto 5 concerned The Epsilon Program, a highly influential religious cult that is firmly established within the GTA universe, who greatly believe in the supernatural and alien life. Thanks to the "Geology for Beginners" mission in Red Dead Redemption 2, a theory that suggests that the Epsilon program exists between both games has been developed.
The substory in question involves an eccentric man named Francis Sinclair, who tasks Arthur Morgan with collecting a series of rock carvings that eventually point to the supernatural conclusion of Sinclair being a time traveler. Within the tenants of the Epsilon Program, a man named Kraff is considered one of their primary leaders and points of worship. It is said that those who are integral to the Epsilon Program are descendants of Kraff, and will thus sport a large birthmark across their face. Sinclair has just such a birthmark, with his alien-focused rock carvings giving further credence to a link to the Epsilon Program and thus linking both Red Dead and GTA even further.
Grand Theft Auto Online: John Marston
Another direct link between both GTA and Red Dead can be found quite easily within the massively successful Grand Theft Auto Online. The element of GTA Online in question regards the original character creation system for the game, which allowed players to choose from randomly cycled parents and grandparents to produce their own GTA Online character in a more personalized and unique manner.
In this early version of the game, players had the chance to select John Marston as their grandfather, in what was a very on-the-nose reference to Rockstar's iconic Western franchise that would establish the Red Dead Redemption protagonist as existing within the GTA timeline. While theories surrounding this addition to GTA Online are more easily dispelled, as the presence of Marston could be regarded as merely a non-canon Easter Egg, the addition of so many other links between the two franchises make this theory hard to ignore.
Grand Theft Auto and Red Dead Redemption: The Sasquatch Hunter
The other main theory that suggests both GTA and Red Dead take place on the same timeline comes with the presence of a very similar Sasquatch hunter across both franchises. In the supernatural Undead Nightmare DLC for the first Red Dead Redemption, John Marston comes across a grizzled hunter in the woods that sports a pelt hat and a gruesome scar clean across his left eye, who is hunting for Sasquatch.
An extremely similar situation arises in a side mission for Grand Theft Auto 5, in which Franklin can find another hunter within the woods after the player attains 100% completion. Although visibly younger, the hunter in GTA 5 has the same furry garb, has the exact same scar over his left eye, and is even also hunting Sasquatch. While many will dispel this theory as coincidence given the near-century of time difference between the two games, there is another factor that gives the theory much more validity.
In GTA 5, the hunter can be heard saying how he wishes to make his great-grandfather proud, with it being entirely plausible that he is referring to the hunter featured in Undead Nightmare, the timeline matches up perfectly as a result. While some of these theories may be contested when taken into account individually, the sheer volume of them combined is enough to convince even the biggest skeptic of a very plausible timeline link between Red Dead Redemption and Grand Theft Auto.