YMMV / A Mighty Demon Slayer Grooms Some Ponies

• Audience-Alienating Ending: Chapter 8 ended the series by revealing Celestia and Luna were actually Tirec and Grogar in disguise, their benevolent reign all an act while they waited 5000 years to get the Rainbow Of Light from Megan before enacting Revenge. This was overwhelmingly lambasted as extreme Canon Defilement, its Foreshadowing^note Megan's description of a woman her father disappeared with, the prophecies of Megan's "second coming", andthe prophecy made by the G1 Twilight, being grossly inadequate for something so massive, and making absolutely no sense that villains who wanted revenge so badly did so much good for them intern and would wait on such a far-off and convoluted means. While this chapter was removed in response, the backlash caused the author to lose interest in and abandon the work leaving it practically only remembered by fans for the infamy of its original ending.
• Canon Defilement: Chapter Eight's reveal that the Royal Sisters were in reality two of ponykind's most ancient and monstrous enemies and that everything they ever did to protect Equestrian was to set up their vengeance against ponies and humans was... not well received, let's just say.
• Hilarious in Hindsight: Fans who loathed Chapter Eight for the controversial Reveal that 'Celestia' was Tirec all along got the last laugh, as the G4 version of the character appeared as the villain in the Season 4 finale as an old adversary of Celestia. It's safe to say this plot development was kicked from the realm of possibility at escape velocity. The same applied when Grogar also appeared in the Season 9 premiere. Humorously, this did also lead to a canon team up between the two and three other villains. The series finale pulls a reverse on Chapter Eight by revealing that Discord was disguised as Grogar the whole time!