I just thought Danzou's arm was broken or otherwise damaged and he had like some support bracing or whatever on his arm, that still might be the case, but seeing the weird chakraflow(i think?) in his eye/arm when the other bodyguard used his Buyakugan, it might be something completely different.. not sure whats going on there, but i still don't think those are weights on Danzou's arm >_>