Yuki Kajiura is a Japanese composer, arranger and music producer. She has provided the music for several popular anime series, such as Sword Art Online, Puella Magi Madoka Magica, Fate/Zero, The Garden of Sinners, Pandora Hearts and Demon Slayer: Kimetsu no Yaiba.

Sword Art Online is a Japanese light novel series written by Reki Kawahara and illustrated by abec. The series takes place in the 2020s and focuses on protagonists Kazuto "Kirito" Kirigaya and Asuna Yuuki as they play through various virtual reality MMORPG worlds, and later their involvement in the matters of a simulated civilization. Kawahara originally wrote the series as a web novel on his website from 2002 to 2008. The light novels began publication on ASCII Media Works' Dengeki Bunko imprint from April 10, 2009, with a spin-off series launching in October 2012. The series has spawned twelve manga adaptations published by ASCII Media Works and Kadokawa. The novels and the manga adaptations have been licensed for release in North America by Yen Press.