Board Thread:Naruto Discussions/@comment-2156952-20140715101620/@comment-1018594-20140715235817

Why did Obito's eyes start bleeding when he used Kamui? He's never had that problem before.

Even though it might take extra effort to open up dimensional vortexes, he had Sakura transferring her chakra and, presumably, her medical ninjutsu to him because the Strength of a Hundred Seal spread to his body.