Have you ever heard of the idea that by the end of s4 Will has lost everything that was used to bring him back from the Mind Flayer possession back in s2?
Jonathan mentioned Castle Byers and how they’ve built it together. In season 3 Will destroyed the Castle Byers.
Mike mentioned how the day they’ve met on the swings and Mike asked “if Will wanted to be his friend” was the best thing he’s ever done. In the end of season 4 Mike contradicts himself during his speech to Jane, saying that “his life have started the day he found her in the woods” (also the same day Will disappeared)
Joyce mentioned Will’s birthday: March 22. The same day that was completely forgotten in season 4, when Jane was bullied at the Rink-o-Mania. No one, including Will, has mentioned his birthday. I might say though, the Duffers confirmed that they simply have forgotten about this, which is weird considering how they could have used any other day on the tape. It also becomes more weird that in season 5 Joyce says “11 years old boy” speaking of Will in season 1, however we know that by the time Will went missing he was 12 already (it is seen on Jonathan’s “missing kid” poster).
There was also a postcard right behind “Will the Wise” artwork that says “I forgot your birthday”
Out of all of this the Birthday Gate theory was formed. Some people believe that Mind Flayer or/and Henry have started to slowly erase Will from the existence, since their previous plan (of possession) has failed due to love and support of his friend and family. And I love this idea SO MUCH!! I personally view this more as the way to make Will lost all the hope and faith, and also bring one of Mike’s biggest fears to reality (you can’t make me believe that his biggest fear is losing Jane only, I feel like this actually works for most of his friends BUT especially for Jane and Will).
Oh, the possibilities we could have had….💔
This sketch is slightly related to his erasure? This is how I see him being erased in real-life, Mind Flayer’s physical veins slowly sprout inside his body so it could later be used as a puppet. And I kinda like to believe that Vecna’s body was formed similar way (Henry being slowly erased, at least the hopeful part of him, which could have been brought back by Patty)