LOOOOOOL when will people LEARN that, that wasnt his ****ing perfect susanoo you !@$# If it was his PS literally all of those hands would get chopped the fk down. Hands down. If he actually had PS he wouldn't need to armor up Kurama. PS alone is enough to take down that buddha thing since they are the same size accept the buddha's hands makes it seem like it is much bigger whilst it is not. But for your question madara's ''INCOMPLETE'' susanoo ran out because of lack of chakra people say its because of the slaps buddha put into him while its not. Susano'o defense is the biggest defense in naruto history his Chakra simply ran out of chakra. Also if his susano'o (which let me remind again wasn't even PS) stayed a little longer all of the Buddhas hands would of been chopped down. I'm not a fanboy. Just saying. HASHIRAMA MADARA FTW!
