Calling the Old Man Out: Gaara finally calls out his father for his terrible parenting. Not only does the Fourth Kazekage take it, he one-ups him by calling himself out, admitting that after everything, he has no right to call himself Gaara's father.
Fighting Your Friend: As a consequence of the Edo Tensei, several loyal and deceased shinobi are revived and forced to fight against their comrades, some of whom were the friends and family in life. Rather understandably, this pisses off the whole lot of them.
Gaara's character arc comes full circle after his father, temporarily revived, finally confesses to him the truth of his birth. He reveals that his uncle Yashamaru never hated him (he actually hated his brother-in-law) and that his mother died loving him.
Tobi is not Madara Uchiha.
Wham Shot: Chapter 559: The body that Kabuto used to blackmail Tobi is finally revealed...and it's the real Madara Uchiha.