SPOILER ALERT!
One Piece Vol 57: Paramount War

This is the craziest, messiest, busiest, and best drawn battle I've ever seen.
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Ahhhhhhhhhhhhh! Okay, breath. Just breath...ahhhh!
Basically, fighting. Devil fruits you wouldn't dream of, learning Ivan and Kuma knew each other and Kuma's fate. We learn about Ace's past and how he became Whitebeard's son. We meet OARS, JR! I learned to love Garp just a bit. Luffy and Whitebeard talk to each other as if equals. We learn what truly makes Luffy strong:
(show spoiler)(Hawkeye Mihawk) "It's not his powers or techniques. He possesses some quality that makes people want to help him. And in these waters...that is the most formidable power of all!"