Let’s tally it up for the betting pool at work: One main hero (Will or Eleven), one beloved side character (sorry, Murray Bauman—your Russian-speaking days are numbered), and every single demogorgon that exists, plus Vecna. The town of Hawkins will lose about 80% of its background extras, because the Upside Down loves a crowd.
In conclusion, prepare for a bloodbath that makes the Red Wedding look like a tea party. No one is safe—except maybe Dustin’s hat, because that thing is immortal. Now if you’ll excuse me, I need to go pre-order my "Will Byers: He Was The Real Superhero" commemorative mug.