Board Thread:Questions and Answers/@comment-1031724-20161029080114/@comment-27929601-20161108120326

I am pretty sure that they turned into Mindless Ones, while their skin was desintegrating as they were absorbed into the dark dimention, they appeared to get covered in some kind of rocky subtance, leaving them with only a trace of their purple eyes. It looked like Kaecilius turnes into a Mindless One, so he technically he has eternal life and will form part of Dormammu for eternity.