Thriller Bark

Blackbeard invading Impel Down might be too much of a rehash, so having Shiki beating him to the punch ( barring an alliance ) would be a nice twist. Could see Oda even tossing a red herring by revealing BB destroyed the Doors of Justice to make us think he did the same with Impel Down, only to spring the epic return of Shiki on us, having absconded w/ ID with his flying island fortress.

What would be the purpose behind such an attack? Well, besides the obvious display of strength, intimidation, and all around "Fuck you" to the WG, there's a certain prisoner currently housed there who could prove a very valuable asset. Who else but Doflamingo?

I'm predicting Doffy's family are gonna be stripped of theer devil fruits by the BB Pirates, possibly as the price and willing sacrifice Doffy must pay for his freedom or something else BB ( or Shiki ) have to offer. I can't decide if it'll be Blackbeard or Shiki who frees Doffy, but a potential secret alliance between the two could account for everything I've outlined.

Speaking of Doffy, I believe he's one of many other big names who'll be popping up in Kano alongside Shiki; this will be the oncoming battleground where the threat of Rox truly begins emerging from the background. Unfortunately, Doffy may see himself being downgraded from "Ten Yasha" to Nine-Yasha" after somebody ends up removing one of his fingers!

"Say what?" I say that because I believe Doffy will be playing the role of these notable creatures from Chinese folklore, including the famous tale of Journey to the West: the nine-headed bird and the 9-headed Bug

Both monstrous birds who ended up having a head torn off by a Celestial Hound. OILER="bird"] [/SPOILER]

Who would be playing the role of the Celestial Hound in this case? I can think pf some: either Blackbird ( lots of Celestial Hound lore ingrained in his character ) if Doffy decides to get all uppity with him at first.