Accidentally-Correct Writing: Yuu's method of using magic in this story involves writing runes on mediums to borrow magic from the world, which had little basis at the time that it was established for the story and was meant to be a shoutout to Fate/Prototype. Come the release of Book 7 of Twisted Wonderland, this rang true as it's mentioned in Book 7 that specific species of Fae are actually able to borrow magic from the world naturally, and Malleus is a part of one such species.
Harsher in Hindsight: A future snippet in the author's Tumblr hints at Yuu becoming a Hero with Bad Publicity to the Night Raven College population due to seeing Yuu going against her lane and the overall status quo of Twisted Wonderland. Years later after that snippet was published, Stage In Playful Land would introduce Fellow Honest, who is revealed to be a victim of magical elitism where he didn't have the good luck of being able to get enrolled to a magical school due to his utterly low magic. Now the discrimination Yuu faces is not just about her going against the status quo, but also the students shoving their elitist beliefs onto her by trying to beat her down for trying to get on even ground with the rest of Night Raven College despite being magicless.
Shiina Yuu is established in Chapter 3 to know and is proficient enough in Kendo. Months after the fact was established, the comic adaptation of the first book was launched in the game's first anniversary and the "Yuu" of the comic, Yuuken, was revealed to be the captain of his school's Kendo club.
