nO idEa....maybe hearing of rin's death??
Maybe he unlocked it during the cave in?
Maybe he killed Rin?
Maybe he heard of the Uchiha clan massacre?
Maybe someone fed him lies making his despise the world?
cause it shows that Obitio likes rin, soo hmmmmmmmm.
he help'ed with killing the uchia clan
he help'ed with killing the uchia clan
then WHY do you think he killed Rin? this is a contradiction.