This was the First Project released by Kyoto Animation after the 2019 Arson Attack on their First Studio, which killed more than 30 people. According to The Studio, the Film was finished exactly 1 Day before the Attack.
The names Isabella York and Ashley Lancaster are a reference to the English war of the Roses in which the house of York, under Richard III, fought The house of Lancaster, under Henry VII.
Taichi Ishidate and Shin'ichirô Hatta were planning to attend the premiere screenings in Germany's AnimagiC but both pulled out following the arson attack at Kyoto Animation studio. Music producer Shigeru Saitô instead represented the film.