Splitting the story into arcs focusing on Shulk, Rex, Noah, Mio, and a brand-new protagonist would create a rich tapestry of narratives, each highlighting their unique worlds and struggles. It would give fans the chance to reconnect with beloved characters while introducing fresh dynamics through the new hero and their team. The anticipation of these distinct stories converging into an epic finale would be incredible.

The final act could be breathtaking—a coalition of heroes from across dimensions, each bringing their own strengths and growth, joining forces to tackle the ultimate villain. Perhaps this "big bad" could be an entity that feeds on the destruction and division of worlds, a being that represents chaos itself. The heroes would have to not only fight but unite their realities to overcome it. And when they do, it could lead to the creation of a new, harmonious multiverse where everyone can live free of fear and conflict.

The emotional stakes would be enormous: Shulk drawing on his resolve from his journey, Rex finding strength in the bonds he’s built, and Noah and Mio defying fate itself. The new protagonist could represent hope for the future, someone who ties all their stories together. Imagine the themes of unity, destiny, and courage woven into a climactic showdown—a fitting tribute to the Xenoblade saga.