Red Dead Redemption 2 featured many Easter Eggs that cannot be explained through normal means, and Rockstar should have seized the opportunity to use them to make a sequel to Undead Nightmare. The choice not to do so disappointed many RDR fans new and old, and with so much to work with, it seems a real shame for the company not to take advantage of the many supernatural phenomena in its game. Fans will just have to settle for mods, and hope against hope for another zombie-filled adventure in the meantime.
Undead Nightmare is a self-contained DLC story for the original Red Dead Redemption, in which John Marston finds himself in a Wild West overrun by the living dead. John has to venture throughout the game's map in order to find a cure for the zombie plague that has infected his family, and he eventually does after some ridiculous happenings. The complete story of Red Dead Redemption's DLC is tough to explain, but it's widely regarded as one of the best DLC packs in the world of gaming, and is beloved by RDR players everywhere. It's much less serious and more fun than the base game, and provides a refreshing and (relatively) light-hearted break from the doom and gloom that surrounds both Red Dead Redemption games.
The original Undead Nightmare started its zombie plague with divine punishment, but there are a few RDR2 Easter Eggs that would provide good possible explanations for another outbreak. Since it was non-canonical, there's no worry that a sequel would get in the way of its story, or the base game's if a second Undead Nightmare also ignored canon storylines. If it didn't, then there's the possibility that players would've controlled Arthur Morgan after his death, and walked amongst the risen dead as one of them. Arthur post-RDR2 could've become a better protagonist after the events of the game.
RDR2's Supernatural Sites Could've Kicked Off A Zombie Apocalypse
There are many points of interest that players can find in Red Dead Redemption 2's map with things that can't be explained naturally. Among others, there are aliens, time travelers, witches, vampires, and pagan cultists, so the game is spoiled for choice as to possible explanations for the next zombie outbreak, and that's if it would've chosen not to create its own just for the DLC. The original Undead Nightmare saw the undead apocalypse kick-off due to a man named Abraham Reyes stealing an ancient Aztec mask, which angers a goddess and unleashes zombies across the United States and Mexico. The borderline ridiculous nature of the DLC's start, and many of its missions, means that a sequel would have had a lot of leeway when it came to what it included. Red Dead Redemption's silly approach could foreshadow a similar RDR2 satire with Undead Nightmare 2.
Aliens could've introduced a virus from their home planet to Earth, which causes the dead to rise or the living to be turned into zombies. The time traveler Francis Sinclair could've found himself in the events of the first Undead Nightmare and unwittingly brought the plague into the sequel. A witch's curse, or perhaps something similar to the concoction that players can drink in the witch cabin in the East Grizzlies could've started the story. If so, then it could've been a good explanation for the player character being immune to zombification, at least initially. If it decided to be truly bizarre, then it could've started off from the pagan site in West Elizabeth where players can find the Pagan Mask, with a ritual that opened the gates of the afterlife and brought the souls of the dead back to the land of the living. RDR2's Undead Nightmare could've had disturbing side missions in the series, or the most silly, if it chose to go this route. Doing this could've also brought back slain characters like Sean and Hosea, and changed the zombies from mindless victims of a plague into vengeful hunters who seek revenge on the player character for failing to save their lives.
Undead Nightmare 2 Wouldn't Clash With Other Stories
Undead Nightmare is considered non-canon for the series, and its storyline has almost nothing to do with the main one, which is a good thing given the amount of absurd events that occur in it. It deviated from the base game's story and crafted its own, one that takes place some time before the army sacks Beecher's Hope in the "The Last Enemy That Shall Be Destroyed" final mission. At the start, zombified Uncle bites Abigail, who in turn bites Jack, sending John on his quest for a cure in order to save his family. The weirdest secrets of RDR are found in this DLC, which is saying something given some of the spooky things in RDR2. John Marston still dies, and after five months passes in the game, Seth Briars steals the Aztec mask and starts the apocalypse over again, but this time, players control a zombified John, one who keeps his faculties thanks to being buried with holy water.
Since Red Dead Redemption 2 is a prequel to the first game, an Undead Nightmare sequel would've had to be considered non-canonical just like its predecessor in order to avoid clashing with the timelines of both base games and the DLC. Arthur Morgan's tuberculosis could also feature, although some classic Undead Nightmare ridiculousness could be used to magically get rid of it for the sake of plot. RDR has done odd things without explaining them in the past, so it's possible. There's also the possibility of it taking place during the post-game, when players control John Marston, in which case they would get to see his reaction to an apocalypse that took place much sooner, and where the fate of Abigail and Jack is possibly uncertain.
Undead Nightmare 2 Could've Made Arthur A Zombie From The Start
If a second Undead Nightmare did start after the end of Arthur Morgan, then a possibility aside from another John Marston story is for Arthur to rise from the mountain grave he meets his maker in. Players do become a zombie in the first Undead Nightmare, but not until after the main quests are already completed. A sequel could've reversed this and made players undead right at the beginning of the story, and have Arthur journey to either find a cure for himself or right the wrongs he committed in life. RDR2's Undead Nightmare could've been completely different from what many fans expect. Arthur would need some kind of explanation for retaining his rational mind, but there are options for that depending on how the events of the DLC would start. It could've even just done what the first Undead Nightmare did and given Arthur a flask of holy water that he picked up at some point before he died, or that someone from the gang went back and left for some reason.
An Undead Nightmare sequel with a playable zombie Arthur Morgan throughout the story has some interesting implications. Interactions with NPCs would likely be next to nil, unless they were also zombies. Players might've found themselves exploring a map unaided by other living characters to help them on their ultimate goal, instead only finding notes or diaries. Arthur could've been guided by treasure maps in RDR2's zombie apocalypse if he fit more in with the dead than the living. There's no saying for certain what it would look like, but walking amongst the living dead in another Undead Nightmare could be vastly different from the first, in the best possible way. Red Dead Redemption 2 could have had the best DLC of any Rockstar game so far, but it squandered so many opportunities.