In Chapter 629, when Obito and Kakashi fought in Kamui's dimension, Obito revealed a hole in his chest and told Kakashi that the hole was opened by the hell of this world. It didn't seem to be a literal hole in his chest (like the Hollows in Bleach), because it wasn't present in the later part of the battle.
Was this hole used figuratively to indicate that Obito's heart was void of emotions, or did he teleport that part of his chest just before Kakashi stabbed him with Raikiri?