Is Vecna the "big bad" that created the Demigorgons, Demidogs, Mindflare, etc or is he the "general" of the Mindlare / whatever is the ultimate big bad in Season 5?Thoughts on the fan theory that Vecna took will in S1 because Vecna sees himself in Will?
From the looks of it, and how the narrative has played out, 001 / Vecna was likely licking his wounds in the Upside down and turning from the burnt / decayed body of 001 into the slimy body of Vecna, eventually combined with the mine flare re the tentacles and went from there. Now that he's recovered to full power, he's started killing people to create doorways to the real world in order to eventually find and kill Elle before becoming all powerful or whatever he wants. I don't think he would have had the power to have taken Will, or if that was the case what was he doing between seasons 1 and now?