Chitanda suffers from some sort of neurological disorder that affects her memory and prevents her from maturing beyond the mentality of a four-year-old.
Oreki may or may not have had a crush on Irisu. He shows an uncharacteristic level of enthusiasm at creating a fitting end for a movie, something that even his friends repeatedly take note of. When Oreki later learns that Irisu was manipulating him the entire time in order to go with her preferred ending it sends Oreki into a funk that goes on even going into the next episode, the 11.5 ova.
Broken Base: Opinion on the ending of the anime is split between those who thought it ended on a logical and satisfying note and those who were disappointed that none of the UST was adequately resolved. It doesn't help that the novel series itself hasn't finished yet and the anime only adapted it up to the 4th volume.
Fan-Preferred Couple: Some popular fan pairings include Oreki x Satoshi, Oreki x Irisu, Eru x Irisu.
Friendly Fandoms: With The Irregular at Magic High School due to the incredibly similar protagonists and style of the anime adaptation. This leads to many fans of these series finding out about each other when they hear about their similarities.
Ho Yay: Oreki x Satoshi is a surprisingly common pairing.
Irisu herself. She is emotionally crippled due to being the heir to her family's business, meaning she has to shoulder the burden of running a company before she even graduates from school. The result is that she can't really make any meaningful relationships and comes off as a Manipulative Bitch. She is also secretly jealous of Chitanda's childlike innocence, as she represents the childhood she always wanted but can never have.
