Okay, I have a byler theory, so basically the entire story was made up by mike to help himself cope with will's death. Dustin actually died as a baby but Mike had him as an imaginary friend, that's why he didn't have teeth. Lucas was real and alive but him and mike don't talk, Lucas experiences really bad bullying irl, and never stands up for him self. So mike made him really stubborn and smart. Eleven was made up by mike also he gave her powers, and made her super epic so he HAD to fall in love with her, he gave her a sad backstory so he'd feel guilty if he didn't. BC all along mike was in love with his best friend Will, but was in denial. When will never came back from mikes house he made up the story that will was taken by the demogorgon from d&d which he and will both liked but never had enough friends to play.
BOOM MIC DROP