What exactly do we know as of 5.3 about the sound that was heard before Amaurot fell?

[ShadowMeowth]

It'd be very interesting if we had discovered it, and revealed it to Hydaelyn right before we were Sundered. Remember, Midgardsormr had a pact with Hydaelyn and was protecting something in Silvertear Lake, whatever is there is incredibly important to what's going on. Whether that's the path to Hydaelyn herself, the seal to the cause of the Sound, or something else entirely is the question.

Hmm. The equivalent of Silvertear Lake in the First is called "the Source". I doubt Azem would have told Hydaelyn anything, they were neutral and if anything I would have seen them telling their former comrades in the Convocation rather than Venat. But it could be possible that you are onto something. Actually, if you dive into the Source Lake, there are strange crystalline structures near the string of isles of Sullen. To me, there are two main possibilities: 1) the Source is where Hydaelyn dive-kicked Zodiark and sundered the star, being some sort of shared link between the shards, 2) it is the literal "Source" of the Sound. Both possibilities are relevant enough to have Sormr as a guardian there.