Runescape Expansion Speculation

So as we all know, in this year's Runefest (2016) during the 2017 reveals section our favourite mod Osborne revealed expansions to us! For those of you who don't know, the expansions work is that every three months, they will release a massive chunk of content all on one day with no extra batches and enough content to keep you occupied for the next three months until the next expansion. 

They have also confirmed later that there won't be any separate fees for these expansions, they're just normal updates, but much bigger.

So far they have only revealed the first expansion, which is going to be the long awaited Menaphos. All the relevant information can be found on either their twitch channel under past broadcast, or uploaded to youtube, this thread is meant purely for speculation on what could happen, not on what we already know. (don't let that stop you from discussing potential desert series quests though)

let's kick things off by listing some potential expansions (keep in mind this is pure speculation, nothing is concrete and will most probably change):

June 2017 : Menaphos (this is pretty much confirmed)

September : Arposandra and potentially the conclusion of the Gnome series. Will we finally see what Glough and Glouphrie are up to? I personally hope that this will come to pass as the gnome series is currently the oldest series without a new quest in quite a while.

December : Underwater City with the conclusion of the Pirate series (or start of Xau Tak's story) This has a lot of potential to happen, as we all know they revealed that the next boss is going to be related to Xau Tak, and what better way to introduce a lovecraftian boss than in an underwater city? not much is known about this horrible entity, but then again, that's what this thread is for.

I'll reserve a couple of posts for some interesting ideas, so start speculating!!