Sephirot, the Fiend is coming.

[Naraku_Diabolos]

http://finalfantasy.wikia.com/wiki/Sephirot

It's Sephirot. A reference to the fiend in final fantasy VI

They probably wanted to leave the Sephiroth avenue open for something else in the future possibly..

The only Sephiroth reference we already had was in 1.0 with Nael van Darnus. So if you did not play 1.0 of FFXIV, you're out of luck because the way the storyline had him was a bleeding Sephiroth reference.