The who is always relative, it's a non-eternal identity, it's made out of definitions, concepts, beliefs, thoughts, meanings... that change all the time.... and this question can point you in the wrong direction and you Will just waste time. So if your doing contemplation I think a better question to ask is "What am I?". another point I want to make is that All questions are really pointless when it comes to realizing your existential nature, Truth.... yes it's  useful for beginners but after a while you have to drop all of the contemplation questions and just simply put your awarness on awarness without asking any question and be that. There Will be no need anymore to ask this type of questions once you realize what You are. The only thing that Will remain is being and that's the answer.   A video I watched that gave me the download to share that, below "Enlightenment is just 4 seconds of the journey" ~Gabe Salomon  (realize enlightenment in a few minutes)