Ever since the truth about Itachi was revealed I've always been curious about the relationship between Itachi and Obito behind the scenes in akatsuki. According to Obito he knew alot more about Itachi then he thought and If Itachi knew about Obito's secrets he would be dead by now. According to Obito the uneasy alliance started at the Uchiha clan massacre and after that time Obito let Itachi into akastsuki. Itachi was probably happy with this considering he could keep an eye on Obito making sure he would'nt go against his promise and attack the leaf or Sasuke. However, my question is what did Obito gain in allowing Itachi into akatsuki?