This chapter all but confirmed Rocks is the Man Marked by Flames but no one is talking about it or paying attention to it >>282003391
This page here specifically connects Davy family to the Underworld

>Rocks is a Davy
>Davy is tied to The Underworld, the note confirms. The same Underworld Man Marked By Flames trades in
>Rocks burned in the destruction of God Valley after being left for dead
>ship burned black just like Black Pearl from Pirates of the Carribean
>sails around sending people to Davy's Locker with his whirl pools, just like Davy Jones
>crew mates who abandoned him on the island all burned to death, BM and Kaido by lava, WB also by lava but from Akainu
>the only guy strong enough to hold a poneglyph solo
>promised to return to Imu
>Is a reference to Shishio from Ruroni Kenshin (Oda was the apprentice there and draws much inspiration from it), a former strongest swordsman of his era who was betrayed and left for dead after being betrayed and burned alive before basically becoming the scarred by burns man with fire powers

The flashback and reveal of Rocks is because MMBF is showing up this very arc. Elbaf is connected to Underworld trading. The Adam tree wood Franky bought was from The Underworld, it came from Elbaf. The children Caramel was selling in the Underworld, also on Elbaf.

Imu is currently in Elbaf. Remember when Rocks promised to return and face off against Imu? That mother fucker is coming back this very arc to make good on his promise. Mark my words.