Quote Originally Posted by AdamuKun322 View Post
Well, Nero could possibly be the 2nd to last boss. Spoiler (He mentioned a power stronger than Ultima Weapon atop the tower).
That or...

Nero will escape with the "Power greater than Ultima Weapon" to set the stage for a future event in the Main Storyline and a future Main Storyline Boss fight or Main Storyline Final Boss fight at the end of the CT storyline.

If that does happen then we know part of what to expect in the Expansion storyline.