That wasn't even part of the current 1.0 storyline anymore!
The name of the 3.0 expansion is called "Shadow of Avalon," and this is also the first version where the Ring of Ouroboros ritual appeared.
The descent of the Fallen Celestial Marshal occurred outside the main plot. To be precise, this event took place in the trailer of version 3.0. However, the Shadowy Celestial Marshal of Avalon only descended after the main boss of version 3.0—that is, the Fallen Celestial Marshal that descended upon Star Antimony—was defeated.
The "someone" who once served as a puppet of Star Antimony and now independently summoned the Shadowy Celestial Marshal is Isabel (Doll).
—This is precisely the core of the conspiracy of the kingdom of Star Antimony, and the reason they dared to directly attack Avalon.
