In the original novel's version of the flashback scene, Ophelia was pregnant with her only known human child.
The epilogue sequence is original to the anime: volume 3 of the novels ended with the grand aria's disappearance.
Novel author Bokuto Uno wrote an extra short story titled "Encore", included with the Japanese Blu-ray set, that acts as a coda to this episode and volume 3 of the novels. Miligan is punished by the surviving members of the Campus Watch for taking the Sword Roses into the labyrinth against student council orders, while Carlos Whitrow is memorialized with a recording of one of their vocal performances played over the school's P.A. system.
In the original Japanese, Carlos Whitrow was assigned male at birth, but usually uses the feminine first-person pronoun "atashi", which tends to denote queerness or effeminateness when used by males. The English subtitles of this episode refer to Carlos using "he/him" pronouns; however, in the dub, Alvin Godfrey uses "they/them", following the example of the English translation of the novels where Carlos is interpreted as non-binary.