One of the biggest lingering mysteries surrounding Stranger Things is how Will Byers managed to survive while being stuck in the Upside Down. The character, played by Noah Schnapp, spent the majority of season 1 trapped in the dark dimension. The effects of his tragic situation went on to have even more serious consequences in Stranger Things season 2.
In the years since Eleven was forced into experimenting with her telekinetic powers at Hawkins National Laboratory, her contact with the Demogorgon and her defeat of Henry Creel unknowingly opened a rift between parallel dimensions. This rift allowed the creature to create portals between the real world and the Upside Down. The alternate dimension mirrored the human world, although the parallel universe lacked light and the air was toxic. The Upside Down was also home to the Mind Flayer, who controlled all Upside-Down organisms using a hive mind.
In the debut episode of Stranger Things season 1, Will was taken into the Upside Down by the Demogorgon. The details surrounding his abduction were never clarified in the Netflix series but the Stranger Things comic miniseries published by Dark Horse Comics filled in many blanks. While attempting to evade the monster, Will hid in his backyard shed. He shot at the Demogorgon with a hunting rifle but was still transported to the parallel dimension. Will spent nearly a week in the Upside Down, and it was a miracle he managed to stay alive. During his ordeal, Will tried to communicate with his family and friends. The hope displayed by his mother as she fought to save him presumably gave him the strength to survive. That may have been true, but the comic book series gave more insight into Will's journey of survival.
How Dungeons & Dragons Helped Will Survive The Upside Down
When Will was first transported into the Upside Down, it reminded him of a Dungeons & Dragons campaign. The young boy envisioned himself as his D&D character "Will the Wise" and bravely fought the Demogorgon by unloading all the ammo in the hunting rifle. This scared the monster off, giving Will time to explore the mysterious realm. He was an expert at hiding from the Demogorgon on various occasions, which became key to his survival. Through his D&D experience, Will knew it was important to help others, but he was too late when it came to Barb. He did, however, manage to save Nancy from the Demogorgon when she found herself in the Upside Down. With no way out, Will took shelter in the Upside Down's version of Castle Byers. As his strength grew weaker, the Demogorgon abducted Will while unconscious. His body was taken over by vines which could have been keeping him alive for the Demogorgon to feed on later, but he was soon rescued by Joyce and Hopper.
It's unclear how Will survived the week in the Upside Down without food and water. The comics made it clear that Will began feeling weaker the longer he spent in the parallel universe. The toxic atmosphere took a toll on his health as he became very sick following his time in the Upside Down, but a lack of necessities would have also harmed his health. It's possible that time moved differently in the Upside Down which added to his disoriented state. However, season 4 recently revealed plenty of information about Vecna's plan in Stranger Things, as well as his position in the Upside Down, meaning that new theories have come to light about how Will could've survived.
Did Vecna Intentionally Keep Will Alive In The Upside Down?
It was revealed in Stranger Things season 4 that Vecna has been pulling the strings behind the Upside-Down's incursion throughout the show's events, so he may have intentionally kept Will alive in the Upside Down. Will was abducted under mysterious circumstances in Stranger Things season 1, and it's still a mystery as to how he was able to survive the ordeal without proper sustenance. However, now that audiences have been made privy to the fact that Henry Creel/Vecna is the self-proclaimed leader of the Upside Down, it means he not only knew about Will's abduction but must have organized it himself. Vecna's connection to Will and his reasoning behind the initial abduction haven't yet been explored, and neither have his motivations for letting Will live while giving many other Hawkins children a grizzly end – but the very final prickling on the back if Will's neck doesn't bode well. It's possible that the leader of the Upside Down wants to keep a connection to the human world through Will and could even want a human host. There's still no certainty around how Will stayed alive during his time in the Upside Down — but that Stranger Things finale hint about Will and Vecna shows that Will survived for a reason.