Quote Originally Posted by Rosenstrauch View Post
As for other possible options:

There is no single being—sans perhaps Zodiark—that embodies Darkness as well as the Cloud of Darkness. The literal personification of the flood of darkness, and the void itself, that consumed the Thirteenth reflection.

Nidhogg is less about Darkness than he is about Blood and Fire. He's also not a primal, so there's little reason to go for him over something more fitting. Tsukuyomi's powers are tied to Moonlight, and Tiamat... was never fought, so we have no idea what she's capable of.
To be honest, the candidate which comes to mind is the Primal responsible for the Calamity of Astral Darkness, namely Bahamut.

Which, based on the SMN 50-60 questline, we didn't even need to fight, but just to be in the vicinity of. Which apparently applies to literally everyone on Eorzea, and implicitly the Source (given the variety of possible backstories for the player character).


Still, I do agree that what we did get is at least handwaved enough that the seams can be ignored.