Part 1 of 2:
Spoiler Warning for those who haven’t done the latest Living World content.
Theorycraft Warning: If you don’t like half-baked fan theories, turn back now.
What We Know: Scarlet is planning an attack on Lion’s Arch and Captain Ellen Kiel is one of the few who is preparing for this onslaught. (You’d think the Captain’s Council as a whole would be more savvy to this threat, but apparently their hubris rivals that of the Arcane Council.) Scarlet has prepared for this attack by amassing a large and varied force and has created and concocted many deadly weapons.
What May Be: We’ll likely face the culmination of those efforts in Lion’s Arch facing off against all these enemies and technological weapons. The Captain’s Council may be caught off-guard but we heroes will be prepared for the threat. We’ll destroy the minions ravaging all across Lion’s Arch and finally take the fight to Scarlet to kill her for good.
Scarlet’s Legacy: But what happens then? Imagine Scarlet, in her dying breath, holds a device at the edge of Lion’s Arch’s harbor. Right before she dies, she activates the device and falls into the water. The residents of Lion’s Arch break into celebratory revelry, but it doesn’t last for long. The ground begins to violently shake. Could this be Scarlet’s trump card? To destroy Lion’s Arch in one final desperate act via earthquake? If only.
The floor of the harbor begins to rumble, a split in the ground grows bigger and bigger. Suddenly it erupts and something massive emerges: an Elder Dragon!
Good Vibrations: Wait, what? Stop right there. A dragon!? That’s lunacy! Okay, okay. So as epic as that scenario could be, it’s seems a bit unlikely considering this is the main player hub, and I don’t see ArenaNet making that big of a permanent change to the city what with all the destruction that would cause. That and the implication from this would be that there’s been a dragon under Lion’s Arch even before Guild Wars 1 and you’d think there’d have been evidence of some weird going-ons because of it.
Let’s turn to Scarlet’s origin story and her intentions thus far. We know that even before she cracked inside Omadd’s machine she was troubled by a dark influence. She had turned to Sylvari menders for help, but it was to no avail. When she experienced the vision inside the machine, the Pale Tree tried to protect her from going too far, to being exposed to this influence. That makes me believe that the Pale Tree is already aware of this threat, which is likely to be an Elder Dragon what with all the hints we’ve been given thus far.
Scarlet’s actions up to this point suggest that she is searching for this Elder Dragon. She is using her thumper technology to pinpoint the location of the dragon with the use of ley lines. Instead of there being a dragon under Lion’s Arch, what if the significance of the city’s location is that of a huge ley line? Scarlet’s goal may be to tap into the ley line using thumper vibrations, locate the dragon elsewhere and awaken it.