i know who tobi is. (I THINK LOL) if is obito he half zetsu and some medal (cause how he stop soygetsus blade with one hand) i think but just think when he touched the persons back and got the bugs it was on obitos side that got crused so thats y when he tore it off it was zetsu gupe and he took another persons sharingan thats y he didn't mind losing it in izunagi and y he wanted to replace it with something bigger is because he didnt care about the other sharingan, and his motive behind the plan is that WAR ALMOST killed him and he wants to end it so it wont hurt no one else gets hurt the near death experience made him go crazy he wares the mask so people wont run when they see his face cause a half zetsu and half human.