It is actually not really clear what we have seen.
We saw the Ley lines explode, breaking through the surface (why, i dont know. just because they were pierced by the drill? this certainly needs more elaboration…. oh wait.. Scarlet did it) in different directions…
The last pictures were indeed not the Maguuma jungle but more likely Orr, going into the ocean and maybe under the ocean floor.
We then see some teeth, resembling thorns at first, but quickly turning blueish green, oceanic.
So in the end it is not actually confirmed which dragon it is. It could be Mordremoth, but Bubbles is not outside the possibilities.
How could you interpret that as water?
It’s 100% Mordremoth
Here are the facts:
-The leylines travelled west through Kryta
-Then travelled further west/southwest past the Reactor
-Butterflies are flying around in the ‘green’ scene (the small bubbles are sparkflies)
-You see rotting fauna/treesAND the only place in all of Tyria with rotting fauna and trees is TWILIGHT ARBOR which is in CALEDON FOREST. That’s the Nightmare Court headquarters.
Now we now know what the courtiers have been worshiping in that location all this time. Be ready to see new content involving Faolain and her crew!
Logic! Finally! You’ve brought a tear to my eye. All this silly water nonsense is making my head hurt. I fail to see how people saw grass and trees as “underwater.” Most of the things the leylines in the cutscene pass through are all structures people have been to ingame…which are definitely not underwater.