Btw another thing to think about the Lurking Legend
Now i will like him to be Shiki (and he can be him) but he can also be that Xebec dude, let's see:
-We know that the battle between Rocks vs Garp + Roger happened 38 years ago
Ages at that time:
-Sengoku 41Yo,Garp/Rayleigh 40Yo,Roger 39Yo,WB 36Yo,BM 30Yo
Ages now (briefly)
-Oldest Sengoku 79Yo
-Youngest BM 68Yo
Now usually in OP characters hit their prime around 40 to 50Yo and Xebec to be leader of such a formidable group was sure in his prime so 100% > than 40Yo, AND he should have been AT LEAST as strong as the current strongest Yonko (whoever is in your mind) and maybe even more (i don't think that Roger PK is that far from Yonkos like he might be a little stronger but not like mid diffing a Yonko or something maybe defeting all of them 100% but all extreme diff fights) so let's say
At Worst Strong as current strongest Yonko
At Best PK (or even like 1% more i mean he's hype man)
What we know about this Lurking Legend is that
-He will be introduced in Wano.
-He will be the greatest enemy the SHs will face
-And he's a legend
Now:
Shiki, he can be considered a legend,they even called him like that so, there's not much to say about him right now we know something already he escaped from impel down and he's been lurking for 20 + years
(and he called WB Old annoying geezer so he should be younger than WB (dead at 72 so he can be 68 like BM or something around that). And what will make him the greatest enemy ever is the fact that Shiki likes creating complicated plans i mean he waited 20+ years to develop his plan so he can be really really tough even if he is not as strong as Kaido/BM and maybe he is "just" as strong as an Admiral (or even a little stronger) he can still be freaking dangerous if combined with his mind
Xebec, he is THE legend nothing to say about that, the only thing that holds me is his age if he was let's say.... from 45 to 55 he should be today from 83 to 93 veeery far from his prime but still
Rayleigh at 78 was able to fight on pair with Kizaru for a little (and there was a significant Gap between Rayleigh and Roger so an 83 Years old as strong as the PK in his prime should have aged not bad and be at least as strong as an Admiral and he will be tough as hell anyway.
I think both of them are the only possible candidates and they will make a perfect Lurking Legend (they might also comeback both with Xebec convincing BM and Kaido to join him and Shiki)
So what do you say?