How Nero factors into this, I don't know.

Aside from seemingly losing his character development from CT (which was what made me like him in the first place), Nero is a rogue factor. He can't work with Garlemald since he's a survivor of the Rogue XIVth and has made no effort to integrate into Eorzea.

He's going to do something with Omega. Be it help the Garleans, help the Ala Mhigans, or help us, I don't know.