The ending as planned:
The fight is seen in flashes, from Arabella's point of view. Eventually, Roswell is overcome. After so many years of rule, his power is accepted as invincible but in reality has faded from disuse. Lucifer shoves him to his knees and tears out his wings.
Lucifer returns to the doorway where Arabella stands horrified. He rubs a feather from his gloves. He looks at her apologetically, before covering her eyes and sending her home.
Roswell has dragged himself to another room, in which a coffin-like box lies before a neglected shrine. From the coffin, "God" arises. He is human-esque, with a neck that stretches out slowly, grotesquely. Heavy strands of long white hair (which Roswell has been emulating) tumble over a mask. The mask changes from panel to panel, as Roswell pleads for help. Wordlessly, "God" returns to his slumber, leaving Roswell on his knees, bleeding and broken.
He turns to see Gabriel, only half-healed by his brother's deteriorated powers. No words are exchanged, but Roswell is defeated and Gabriel's faith (which has always rested in his brother and no one else) is crushed.
Lucifer walks to the throne room's balcony, looking out over his conquest. He leans against the railing, and it's all he can do not to fall to his knees. His victory is perfunctory, and empty.
The story shifts back to Arabella. She wakes up in bed as from a dream, back in her own room without a scratch on her. She looks around, at a loss. Then rage fills her at the cruel joke that had been played on her. She feels tiny, thrown around by the universe without any evidence that her experiences had been real. She can hear her brother's voice outside and she wants to scream.
Then she feels a tug at her hand, and he's there. That dumb pervert is sitting next her wearing normal mens clothing for once and finally, she is happy to see him.