There's also a theory about Eternum Nocturne having entered Zed's timeline and is the reason why Eternum Nocturne keeps referring to himself as "We" and the current time as "This place" and it's possible that Eternum Nocturne is just a more corrupted version of the current Nocturne.
Here's some of Eternum Nocturnes Quotes:
"We transcend time"
"Cross over"
"This place disgusts me"
"The first are we the last are we"
"We are one