Skagboys just out for the buzz on drugs, to total junkies. It shows how their attitudes and behaviour start to change as they become more defined by the drug and the culture around it". In 2012, Welsh said the prequel was actually initially written as part of "Trainspotting" but was not used in the published version. He later decided he would either erase his old work or use it in some way, as "he had a fear that he might fall under a bus and leave behind 'half-written stuff' which people would publish". He said, "I just went through it and
Yuki Yuna is a Hero and blesses humanity. Using a special phone application granted by Taisha, an organization dedicated to the Shinju, Yuna and her friends must transform into "heroes" with magical powers to protect their world from imminent destruction. A prequel light novel titled , written by Takahiro and illustrated by Bunbun, was serialized in ASCII Media Works' "Dengeki G's Magazine" between April 30, 2014 and November 29, 2014. The novel takes place two years before the anime's time frame. Another light novel series, titled , written by Aoi Akashiro and illustrated by Bunbun, began serialization in "Dengeki G's Magazine" on July 30, 2015.