Kuma's arrival on Thriller Bark. We only saw Kuma during the Shichibukai meeting, even Doflamingo had more screentime than him. Indeed Kuma was the most unexpected guest. No one could have called this event, and in the end it was one of the most important twists so far:
- Kuma told Moria about Teach being Crocodiles successor. And we already knew why. These events are the cause for the current situation.
- Kuma gave Zoro a chance to show the readers how far he would go to protect the crew
- Kuma "paw"ed the strawhat crew away from Kizaru, which is because of his experience with them on Thriller Bark
- Kuma is the character who caused the minimal chance to rescue Ace from Impel Down
=> The Kuma-twist is very important …