"Thinking about how Erica's attack that defeated Vecna in the DnD game was a 20. 11 alone failed... Could it take El and Kali turning 001's powers around on him to defeat Vecna in the end?"

With a few weeks left to go until Stranger Things 4 Volume 2 is released on Netflix, fans have been hard at work theorising what might happen with every single plot line going into the final two episodes. One of the biggest talking points? The inevitable fight between Eleven and Vecna.

Throughout the past seasons of Stranger Things, the big bads have all been theoretically linked to Dungeons & Dragons and the campaigns that the party has played. In season 1, we see the Demogorgon come to life after Mike, Will, Lucas and Dustin attempt to fight it in their campaign. Season 2 saw D&D's Mind Flayer make its grand entrance, with season 3 focusing on a physical version of the same creature.

Season 4 brings Vecna, one of D&D's most powerful villains, to life as the actual threat brewing in the Upside Down, and he's also the key figure in Eddie Munson's Hellfire Club D&D campaign.

Fans are now theorising that the outcome of Eddie's D&D campaign might hold a few clues as to what might happen when Eleven finally faces off against Vecna.

READ MORE: Stranger Things fans are convinced Steve is going to die in season 4 and I am terrified

Cast your minds back to season 4 episode 1, to The Hellfire Club's battle against Vecna in Eddie's final D&D campaign.

After coming up short as a team, it falls to Dustin and Erica (a.k.a. the icon and legend, Lady Applejack) to take out the villain and win the campaign themselves. As Dustin rolls first, the camera focuses on the D20, showing that he has rolled an 11. Eddie then proceeds to tell the party: "That's a miss!"

Much like the scene in season 1, where the Demogorgon catches Will in Mike's campaign after he fails to roll a 13 or higher, Dustin's roll might foreshadow what could happen when the group take on Vecna in real life.

Based on what we've seen in Stranger Things 4 so far, we know that the ultimate goal is to get Eleven back to Hawkins, with her powers restored, in order to fight the war that is brewing with an all-powerful Vecna right in the middle of it. As of episode 7, we see that El has unlocked her repressed memories, and it seems like she's finally about to get her powers back. What we don't know just yet is just how powerful Eleven's powers will now be.

Thanks to the D&D scene, fans believe Dustin's roll could hint at the fact that 11 (or, ya know, Eleven) is not enough to defeat Vecna, at first.

The theory continues, suggesting that Eleven's potential loss against Vecna could bring about the possible reintroduction of Kali a.k.a. Eight.

Remember Kali? She was introduced way back in season 2 as Eleven's 'sister'. She was another one of the children who Brenner kidnapped and experimented on, but at some point before the 1979 massacre she had managed to escape. Back in season 2, the Duffer brothers confirmed that they were not quite done with her story just yet...

On the final roll of the dice in Eddie's D&D campaign, Erica manages to roll a 20. It's a critical hit, the party finally defeat Vecna and win the campaign. So, what does defeating Vecna IRL have to do with Kali's potential return?

Now that we've met the rest of the lab children, we know that all of them have powers that mirror 001's telekinetic abilities, as he was the first test subject and the one that Brenner was trying to replicate. Well, every lab child except Kali, that is...

Kali doesn't possess the same telekinetic powers as Eleven and the rest of the kids, but she does possess the same mind manipulation powers as 001/Vecna.

Thinking about how Erica's attack that defeated Vecna in the DnD game was a 20. 11 alone failed, but 011+008+001 = 020. Could it take El and Kali turning 001's powers around on him to defeat Vecna in the end? I don't know, just a theory. #StrangerThings4

OMG- what if kali comes to help eleven during the fight against vecna?? #StrangerThings pic.twitter.com/gDyVeCLBg5

stranger things 4 spoilers . . . . . . since the only surviving hawkins labs kids are are one, eleven, and eight, that means kali HAS to come back. idc how much people disliked her, she was integral to el’s growth and can help stop vecna (and by extension, dr. brenner)

I mean, that DnD game in episode 1 seemed like foreshadowing. Dustin rolled an eleven against Vecna, and the attack failed 😬

Vecna/001's main powers appear to be split between Eleven and Kali, the last two remaining test subjects from the lab: Eleven's most prominent powers – telekinesis and opening gates to the Upside Down – mirror 001's. Eight's most prominent powers – mind manipulation and creating hallucinations/visions – also mirror 001's.

Fans are now theorising that the powers of both 011 and 008, who have the combined power of 001, is what is needed to deal a critical hit to Vecna and defeat the villain. 011 + 008 + 001 = 020?

Guess we'll just have to wait see what happens when Eleven and Vecna face-off against each other in Volume 2 – assuming El makes it back to Hawkins in time, of course!

But based on what the Duffer brothers and executive producer Shawn Levy have teased so far about the finale ("everything goes to hell", "[the final two episodes] punch you right in the heart"), we're terrified we might be about to experience Stranger Things' version of Infinity War.