Now that we‘ve seen and heard a little more of him, I came up with a theory!
MSQ:
I can‘t help but think that Elezenos is Estinien. That we didn‘t see anything of how we got saved by „Estinien“, as Aymeric said, and Elezenos saying “My enemy. My friend. Had I been but a step faster...“ kinda makes me wonder if his identity was the reason they hid the whole scene from us. His face also resembles Estinien‘s quite a lot, the only difference I can see is the eye colour. But as they say, the eyes are the gates to a person‘s soul right? Aymeric also mentioned that Estinien was not a man of many words. Hearing now, that Elezenos still has Zenos‘ voice would explain to me why he did not speak. The fact that Estinien and Zenos both fused with Nidhogg‘s eyes could also hint at a connection. Maybe even that Estinien destroyed the eyes at the exact spot where Zenos had died but a few moments before that. And one more thing that Aymeric said also got me wondering... he said that the „Ascian Zenos“ was distracted by a person who entered the battlefield right before his blade could reach the WoL. Aymeric called that person Estinien, but who else could distract an Ascian who‘s about to kill his and his god’s worst enemy this much but the soul of the body he possesses itself?