* BadassDecay: All of Organization XIII, with the possible exception of Xemnas and Xigbar, who are never seen in a real fight.
* ContinuityLockOut: The author makes no efforts to familiarize the already complex plots of both games to unfamiliar readers.
* CrossoverShip: Felix/Xion, and Axel/Mia, by the end of the story.
* MoralEventHorizon: Alex crosses it in chapter 17. [[spoiler: He might not have been in control of himself, though.]]