So I thought that I posted this the day after I posted the last part, but apparently not, oops, oh well here it is now.

I call my theory The Lost Knight Theory, here is some important stuff from a scene at the end of season 1, the comic con Stranger Things "Thriller" Trailer, and a few parts of the most recent trailer for season 2.

I've put a video of the scene and the trailers on here, please watch them before you continue reading, even if you've already watched them. If you can't watch the video on here for whatever reason, I have put the exact titles as well as a link for each one so you can find them on your own on YouTube. After each video I have a list of what is important for my theory from that video, so make sure you read those as well. Then read the theory.

Have fun!

The kids playing D&D a month later 1x08 [Stranger Things]
Posted by TvSeriesandShips

[There should be a GIF or video here. Update the app now to see it.]

https://youtu.be/SR7WKhYmIVE

Important things:
1. Will beating the Thessalhydra
2. The lost knight

Stranger Things | Season 2 Comic Con "Thriller" Trailer [HD] | Netflix
Posted by Netflix

[There should be a GIF or video here. Update the app now to see it.]

https://youtu.be/vgS2L7WPIO4

Important things:
1. Dragon's Lair knight
2. Will's first Upside Down vision (also when he hears the voice say his name)
3. The monster in the clouds
4. The desk next to Mike being empty
5. Will in the chair with a scientist (possibly just a doctor but it looks like they are in Hawkins Lab so I think it's a scientist) and Joyce on either side of him
6. Will's plaid shirt (he wears it through most of the trailer)
7. The portal in Hawkins Lab getting burned
8. The hallway Will runs through
9. What El is wearing when we see her
10. The portal El's hand goes through

Stranger Things 2 | Final Trailer [HD] | Netflix
Posted by Netflix

[There should be a GIF or video here. Update the app now to see it.]

https://youtu.be/R1ZXOOLMJ8s

Important things:
1. "If anyone knows how to destroy this thing, it's Will." - Mike, from the final trailer
2. The person falling on their knees

Ok, now, theory time.

We all know that this show is all about foreshadowing, so this theory will make sense once you read all of it.

I think that this season will be about them trying to get El back, just like Season 1 was about them trying to get Will back.

I believe that the monster in the clouds is the Thessalhydra. Hydras in mythology have multiple heads (the monster in the clouds looks like it has several necks, which would imply several heads) and they could spit fire. Keep in mind that in the D&D game Will beat the Thessalhydra.

I believe that when they mentioned the lost knight that it was referencing a character. I think the character being referenced is Will. I think this because he was lost through most of season 1 and, in medieval times, knights were all men.

The knight in the arcade game, Dragon's Lair, gets killed by getting burned alive by a dragon. I've done some research on Dragon's Lair and the point of the game was the player, playing as a night, would try to rescue a princess from a castle where a dragon lives. The knight's name is Dirk the Daring, I mention that because of the parallelism between that name and Will's D&D character, Will the Wise. To further explain why I think Will  is the lost, right after we see the knight in the game crumble after being killed by the dragon we hear something calling Will's name.

I think that Will has developed powers, similar to those of the Demagorgon, where he can travel between the normal world and The Upside Down. We sort of see this when he mentally travels there in his visions. So, because he doesn't know what's happening to him, he talks to Joyce and she takes him to Hawkins Lab where they run tests to see what is going on, which is what I think is happening in the scene where he is in the chair with the scientist and Joyce on either side of him.

Eventually I think that he discovers that he can make portals to The Upside Down, just like the Demagorgon make portals to The normal world, and he talks to his friends about it. This is important because we see that the main portal, the one from Hawkins Lab, gets burned by someone using a flamethrower. Because the portal got destroyed there is no way to get back there without someone, or something, making a portal, and so the only way they could get El back is if a new portal was made. When Will finds out he can make portals he decides to go to The Upside Down to get El back as a favor to his friends for being so determined to get him back when he was missing. They go to the school, since that is where El disappeared, and he makes a portal in a hallway.

We see him running down a school hallway in the Upside Down, which many people probably thought was just happening in one of his visions, but I disagree, I think he traveled there. He seems to be getting chased by black most of some kind, I think that most is smoke from the fire of the monster (which they've decided to call the Thessalhydra, just like they decided to call the monster from season 1 the Demagorgon, even though it wasn't actually a Demagorgon) and he is being chased down the hallway by the "Thessalhydra". He finds El in the school, but the two of them get attacked by the "Thessalhydra" before they can get out of The Upside Down.

They work together to defeat it, but Will end up killing it. If you wonder why I think it's going to be Will that defeats the monster this season here is a direct quote from Mike in the new trailer. "If anyone knows how to beat this thing, it's Will."

However, in the process of the fight, Will gets mortally wounded by the fire from the "Thessalhydra". He knows he's going to die so he tells El about the portal and gives her his shirt (the plaid one) because, as we know, The Upside Down is cold. She puts his shirt on and then goes to find the portal he told her about, she finds it and goes through.

Now, the person falling on their knees in the new trailer. I think it was Joyce. What they are wearing looks very similar to what Joyce wore throughout season 1, so, maybe El tells her that Will is dead, and she falls to her knees because she cannot bear to stand any longer.

Now, some of you might be wondering why I think El is actually wearing Will's plaid shirt, because that is a huge stretch, isn't it?

No. I don't think it is, and here's why.

Here is a picture from the trailer of Will wearing his plaid shirt.

Here is a picture of what we see El wearing when she appears in the trailer

What El is wearing looks extremely similar to Will's plaid shirt, only slightly darker, which could be because it got burned in the fight with the "Thessalhydra".

So, what do you guys think?

I really, really don't want to be right, but I think at least some of what I said is very possible.

If you have any evidence proving anything I said in my theory to definitely be incorrect, please let me know.

I'd love to talk about theories that you have about season 2, because we're getting closer and closer to it's release.

I'm sorry it took me so long to get this part out, I thought that I had posted it, but I realized this morning that I actually hadn't.

Anyway,

THANKS FOR READING!