Here it is. An overview of Xion's arc in my fic (inspiration, "Drakengard" OST), told in the form of mission objectives: Objective: The Wraith Mask accepts the offering which guides your Keyblade. End Xion's lunacy for altruism. Break through her armor, and force her to take your horrific power for herself. Objective: Your best friend may have broken all plans, but he gave you a chance to live, and you can now feel him through the mutual hunger between yourself and your original self. Claim Kingdom Hearts and use its power to save both. Devour anyone who stands in your path. Objective: Roxas and the Wraith Mask opened your eyes to the lunacy you were about to commit. Defeat the assassin you thought to hold all answers, and procceed to Kingdom Hearts and Xemnas. Objective: The puppet no longer follows your advice, and your symbiotic mate steals your power. Return the favor. Accept the Outsider' gift. Draw from the Void and bend the walking black hole in front of you to your will. Save your best friend ! Objective: DiZ's borrowed time is at an end, but no enemy is truly defeated until their spirit is broken. Destroy his inner Sanctuary's inhabitants and quench the bloodlust that has filled yours. Objective: Despite her crime, she was as justified as Riku. Aid her in battle. Show her she can crawl back from the pit once the fight is over.
