Logan

I think that because of a good theory, rocks is that doctor dude that chopper lived with and admired, I forgot his name tho, because he had hair and a personality similar to rocks, but more elderly, so he didn't fight to often, and when he died, he died with a smile, carrying the ancient will of d, he respected luffy's dream to become pirate king, and believed that Luffy could become pirate king instead of him because he had the will of d and the will of greatness like he had, either all of this, or rocks is inside blackbeard, who knows?

if you think about it, Luffy is the one piece, because when he ate the gum gum fruit, it was a great treasure that shanks stole from an enemy ship, possibly one of whitebeard's crew, and after Luffy ate it, WAY later, he learned that it was the Nika fruit, a mythical zoan, vegapunk and some other characters treat Luffy like he is very important, unlike Sanji and zoro, and other main characters, even blackbeard takes careful notice of Luffy, even whitebeard. And it was destiny anyways because everyone with the will of d always smiles when they die, leading to ANOTHER theory, the one that is the doctor that chopper learned from and admired (I can't remember his name) is rocks d zebek, I also don't know how to spell zebek, but this is also supported because he died smiling, looked similar to rocks, and treated Luffy like he was very important, thus, concluding my theory, but you can reply anyway that you want.