One Piece Green: Secret Pieces (ワンピースグリーン：シークレットピースWan pīsu gurīn: Shīkuretto pīsu) is the fourth databook. It was released on November 4, 2010 and follows the series from the start upto Summit War, revealing various secrets.
1. Yonko = Marine HQ + Shichibukai
(here I think Oda meant each one Yonko.)
2. Doflamingo may have signed a different contract with the WG as being a warlord.
3. In the original setting of Blackbeard’s Yami Yami no Mi, he was even unbeatable to the three admirals.
4. There is a big possibility that a pirate from Roger’s crew named Copper or Bronze appearing later in the story, since Roger is Gold and Rayleigh is Silvers.
5. It’s very sure that there would be a pirate wearing eye-patch showing up in the final arc.
6. The only way so far to figure out Blackbeard’s mystery is to think about Ace’s words regarding BB’s age.
So I have something for you mates… The scans of 3 Chapters from this Databook. But I am not gonna make it hidden or available to subscribers only, though it would be really helpful if you consider supporting me on Patreon!