The only way to stop the Princess was for Sota to write her original author into the special, letting the pair reconcile and placating Altair permanently.Team Creators has to wrestle the story out from under her, since the story the fans are making about her isn't matching up with how the special (and therefore this plot) was written to end. On the Audience's side: Altair is able to shrug off the heroes' attacks during the Elmination Chamber Festival, since Popularity Power means love from the fans can overturn Narrative Casualty to keep her in play.

Naturally, this fails, as merely mentioning it caused the plan to unravel.

The creators come up with a plan to stop the Military Uniform Princess from destroying reality, but opt to never tell anyone about it citing exactly this trope until the episode before the plan is carried out.

Selesia can get a needed 11th-Hour Superpower because her author successfully pulled off writing one for her and letting it reach a wide audience.

Both work as the out of universe version of Narrative Casualty: Stories revolve around two principal factors: the will of the author (which gives a character their basic look, personality, etc.) and the will of the reader (who has the power to accept or deny what the author adds to it). Fakir is (apparently) capable of Rewriting Reality, but it's never quite clear if he's making things happen by writing them down, just writing down what would have happened anyway, or a little bit of both.

Ajimu outright calls it a power that would make any traditional writer recoil in horror. Note that this also includes beneficial examples, like Plot Armor or coming up with a last-minute plan this was specifically requested by Zenkichi since he wanted to challenge Medaka with no interference. Things like Contrived Coincidence, Long-Lost Relative, Crash-Into Hello, etc.

Zenkichi ends up acquiring the Skill 'Devil-style', which nullifies Narrative Causality.

The fact that Medaka has become somewhat of a jerk also takes away from her heroic qualities. Ajimu even believes Zenkichi will win because he's more heroic than Medaka because Medaka apparently murdered someone in the past. Since he's the other main character, he's the only one who could conceivably defeat Medaka. So they arrange a falling out between Medaka and her Supporting Protagonist Zenkichi which leads to Zenkichi's FaceHeel Turn. If they stepped down to Big Bad, her loss would be inevitable.

Ajimu is fully aware that the narrative causality of shounen manga is in effect, and avoids directly fighting The Hero Medaka because of it.

Mazinger Z: In one story, the Butt-Monkey Boss reassures his friends Nuke and Mucha, as facing a dire situation, telling that they will not die because they are the Plucky Comic Relief characters, and joke characters never die.

Just because you're in a setting that's perfect for a murder mystery doesn't mean that one is going to happen, right?

Haruhi Suzumiya: A discussion of this idea bookended a two-part episode.

Narrative causality