WARNING: The following contains spoilers for One Piece Episode 958, "A Legendary Battle! Garp and Roger!," now streaming on Crunchyroll and Funimation.
With the Straw Hats still in Wano preparing for the fight ahead, the rest of the One Piece world is on high alert now that the balance of power on the seas has shifted. As some Marines hunt down the pirates that were once part of the now-dissolved Warlords system, the Vice Admirals at the Marine HQ are treated to a lesson in history by former Fleet Admiral Sengoku. Word is circulating that Big Mom and Kaido have joined forces in Wano Country, and the news has the Marines worried that the Rocks Pirates, the most terrifying crew in the history of One Piece, has returned.
With a history largely shrouded in mystery, the story of the Rocks Pirates, Sengoku notes, is not one that younger generations of Marines may be familiar with. While they disliked each other so much that they didn't enjoy bragging about their exploits, it doesn't change the fact that this crew was very clearly made up of some of the strongest pirates ever to explore the Grand Line.
The Rocks Pirates Were A Powerhouse Of A Crew
Under their captain, Rocks D. Xebec, the Rocks pirates had a notorious reputation. According to Sengoku, the crew was so violent that battles to the death aboard their own ship were common. While a reputation like that is frightening enough, viewers learn an even more surprising fact: under Captain Rocks were some other wildly infamous pirates including Big Mom, Kaido and Whitebeard.
This shared history between Big Mom and Kaido means that their current alliance won't be the first time the two have worked together, and knowing that they were once allied with Whitebeard, who held the title of Emperor of The Sea -- as well as the reputation of the strongest man in the world -- is a further testament, in its own way, to their own strength. Knowing how powerful both Big Mom and Kaido are presently is no surprise whatsoever when viewers realize just what kind of pasts these Emperors of the Sea share.
The Bounties Of The Former Rocks Pirates Indicate Their Strength
Fans of the series will know that One Piece's best indication of a character's power level is their bounty. In this respect, Episode 958 reveals quite a few of them. Among the bounties shown were those of the current Four Emperors: Blackbeard, Shanks, Big Mom and Kaido. In addition, fans get bounties of two deceased One Piece powerhouses: Whitebeard and Gol D. Roger.
What is important about the latter two bounties is that they are used as a benchmark for comparison with the bounties of Big Mom and Kaido. With Big Mom's bounty at 4,388,000,000 berries and Kaido's listed at 4,611,100,000 berries, the two still rank lower than Whitebeard's 5,046,000,000 berry bounty, as well as Gol D. Roger's 5,564,800,000 berry bounty.
Together, however, Big Mom and Kaido's bounties easily surpass either Whitebeard's or Roger's: a true One Piece universe indication of the staggering amount of power they possess. Considering the time that has passed between their time on the same crew and the strength they've earned on their own, Big Mom and Kaido are a true threat to the world and one that the Straw Hats will have to bring their very best against if they hope to defeat them.