One of the major takeaways from the Stranger Things 4 trailer is that there will be a clash between evil alien forces and the main group, putting fan-favorite characters once again in situations of extreme danger. The show's main characters are still standing, even though they barely made out alive and hung between life and death many times. In fact, Season 3's ending implied that Hopper was gone for good, but now the fans can breathe a sigh of relief as he is confirmed to return.
Stranger Things is not afraid of killing off key smaller characters, such as Bob, Billy, and Barb, but as the show progresses towards its final episodes, viewers can expect some major deaths taking place in these last two seasons. Presumably, no one is safe when it comes to taking down bloodthirsty creatures, but the direction of some character arcs might be giving off hints of who is most likely to die in this season.
Jim Hopper
At the end of Season 3, Hopper already proved that he can sacrifice his life to save his friends... except he didn't actually die. His character's redemption and emotional moments with Joyce and Eleven gave the viewers hints that his arc was leading to a conclusion, but the show decided to bring him back. The question is: for how long?
It's safe to say that Hopper probably won't die before reuniting with at least some characters of the main group, otherwise his return would seem utterly pointless. And assuming he will spend considerable screen time trying to escape a Russian prison, as the Season 4 trailer implies, he is likely to survive longer than other key characters.
Lucas Sinclair
Lucas is one of the main protagonists and the show didn't actually give any hints that his arc might be coming to an end. However, he is also the boyfriend of Max, who is now in grief. The trailer showed some shocking scenes involving her and the season's villain could possibly be linked to Max's potential new abilities, and Lucas might be pushed to the center of it with her.
If Max is the new target of the upside-down forces, Lucas will stand at her side to protect her, exposing himself to unwanted danger. His death would be the biggest upset of the show and, most importantly, cause another devastating impact on Max, who is set to be one of the most important characters of the season.
Joyce Byers
Most of the show's deaths were adults, and perhaps it's time to take down one of the major ones. Joyce was one of the most important characters in the show, as she desperately tried everything to save Will from his dark bonds. After her children were apparently safe, her plot crossed with Hopper's and that was basically it. Now that Jim is "gone" and Joyce's kids are trying to have a normal life once again, her story might be coming to an end in one final attempt to save her loved ones.
Ultimately, Joyce and Hopper are one couple fans cannot wait to see more of, so it's expected that her death would only take place after they reunite. Or perhaps, just like Hopper did in Season 3, she would be willing to sacrifice herself to save him.
Mike Wheeler
On the other hand, perhaps the show is tired of killing off adults and might surprise fans by taking down the head of the OG party. One of the most important relationships of the show is between Mike and Eleven, and since the trailer teases she will be in danger again, Mike will be at her side at all times. Eleven already went through a lot in the past seasons and she will hardly be a contender to die before the last season.
Even with Mike's non-stop grumbling, he usually stands out as the leader of the group and is ultimately the best friend you can rely on. His death would equally shock fans and the characters, affecting the whole group with the same intensity and ultimately causing the party to splinter. It would certainly be a highly emotional scene with the potential to change every relationship in the show.
Jonathan Byers
Jonathan is a powerful link to many key characters of the show. He is a boyfriend, a son, an older brother, and a friend. He is one of those characters who would sacrifice himself without hesitation if Joyce, Will or Nancy's life is on the line. In fact, taking risks on behalf of the other's protection was pretty much what he has done so far.
One argument that holds back Jonathan's chance of dying is that his family has already been through a lot. It would be bittersweet if Joyce spent three seasons trying to save her son just for the other one to die in this season.
Nancy Wheeler
Nancy is often the brains of the group and the one who goes for the rational decisions, but she is not afraid to step up and face the risks. Her awkward relationship with Steve and the romance with Jonathan was quite entertaining throughout the seasons but right now it doesn't seem like it has too much to add.
Another Nancy and Jonathan mystery is something want in Season 4, and while they both are usually exposed to the same amount of danger, she is more likely to die simply because it is far more unexpected. The impact on other characters would be just as big and could potentially bring the rest of the Wheeler family to the central events of the show.
Robin Buckley
There's no doubt that Robin is a fan-favorite character, but she is also one of the latest additions to the main cast. Therefore, she doesn't have strong links to anyone except Steve, Dustin, and Erica, kind of. Even with not a lot of screen time in the show overall, she had a huge arc development and certainly was not the same person by the end of Season 3.
Her death would not drastically change the course of the show but would be deeply felt by the fans, and that's an approach Stranger Things has been using when killing off characters.
Murray Bauman
Murray is one of those characters that only show up every once in a while, but his energetic personality always brings about a few laughs. While he's not exactly a main character, he's definitely a key one, getting more screen time as the seasons go by. After all, he was a central character in Season 3's resolution.
He's already been confirmed for Season 4, but it is still unsure how he's going to fit in a plotline without Hopper. Most likely he will be one of the first to find out Hopper is alive and will do anything to bring his friend back. Going along with this possibility, he might expose himself to unwanted danger and the worst outcome is not unlikely to happen.
Max Mayfield
Max might be the character in the most danger. Even though new powers are not something that fans really want to see in Stranger Things, Max seems like she might have something to do with the evil forces lurking around Hawkins, and the trailer gives a lot of hints on that.
Moreover, she is grieving her brother Billy. In such a moment of emotional instability, she can end up messing up badly in her actions or decisions. Her death would have a massive emotional impact especially because of everything Max has been through, but it would also make total sense to the direction the show is taking.
Steve Harrington
Everyone loves Steve and no one is ready to lose him, but he certainly is the character with the highest chance to die in Season 4.
While he is a key character of the group, he doesn't have a promising future or a love interest like the others. Expanding Steve's arc to a role of leadership would be a huge redemption for the character, and the show has been teasing he's willing to sacrifice himself to save his friends for quite some time now. Now that the show is ending, it is not hard to imagine this actually taking place by the end of this season, creating a massive emotional gut-punch.