I feel like there's been a couple characters that were talked about before and they've been in silhouette so prob one of them. But not sure which one, it makes me think of the Rocks pirates. Big Mom, Kaido, and Whitebeard were part of that crew so maybe another of them.
Smoker maybe... After punk island and the kids he set off after Luffy
Could be fujitora
Shanks brother
You know what? Yes. I like that
Is the sword dude on the last panel ... Drake? Or a new character?