When Eleven came on the scene in Stranger Things Season 1, she really threw the lives of Dustin, Mike, Lucas, and Will for a loop. This was a superhero — nearly literally — with super powers, who loved waffles and was able to kill demons and creatures from other dimensions in one fell swoop. In Stranger Things 2, we found out there were more "numbered" kids, meeting Eight (aka Kali), who has given herself over to a life of revenge, crime, and looking "bitching." (Who doesn't want that?) But where is Eight in Stranger Things 3?
In Stranger Things 2, Eight convinced Eleven to come join her and her band of merry misfits, all dead set on finding the men and women who helped keep them at Hawkins Lab and destroying them all. Many are gone or dead, but some remain, and Eight, as Eleven finds, loves to squash a bug. Eight's powers are different than Eleven's — she is able to make people see things that aren't really there.
In Season 2, Eight and Eleven split when Eleven knows that Mike and Hopper are in trouble, because they are Eleven's real family, and she has to save them. Typical superhero stuff. At the end of Season 2 of Stranger Things, Eight is definitely alive, but she's not in the picture.
And that brings us to Stranger Things 3. There's no official word that Eight will make future appearances on the show, but the Duffer brothers, who created Stranger Things, are notoriously tight-lipped about their plot lines (duh), so why would they give that away? But, according to Deadline, at last year's Vulture Festival, they did say that we may not have seen the last of Eight. “It feels weird to me that we wouldn’t solve [Eight’s] storyline,” Matt Duffer said. “I would say chances are very high she comes back.” Whether or that means another capsule episode or not, we don't know, but considering that fans and reviewers didn't love separating Eleven from the boys, maybe Eight will be incorporated into Hawkins.
For the record, executive producer Shawn Levy stands by that standalone Eleven episode. "It allowed Eleven to learn about her powers and gain more —which we need for episode nine," he said at Vulture Festival. "Her going away makes that return at the end of episode eight so powerful." In an interview with E!, Levy also underlined that there are probably more numbers out there. "I think we've clearly implied there are other numbers, and I can't imagine that the world will only ever know Eleven and Eight," he said.
If that's the case, how many kids are there? Is Eleven the last one, and therefore the youngest? Or are there more kids that were taken away and given to who-knows-who after Hawkins Lab was shuttered? Eight's presence in the Stranger Things world leads only to more questions for Strange Things 3 (and 4 and 5 and 6...), so bringing her back into the fray would be a good idea. If the previews for Stranger Things 3 show anything, it might be a good idea to have some extra help at Starcourt Mall.