The following is all assuming you are ok with spoilers/are current.

No, Zenos is just an abnormally powerful man who managed to get himself an artificial echo. If it weren't for the experiments he did to get that, he would have died at the end of Stormblood when he cut his throat and that would have been that. Besides, it's Elidibus who is Zodiark. Or at least Zodiark's core. Makes me wonder if Zodiark can even be sentient anymore.