The main themes define the anime's identity and were released during its initial run in late 2021. Artist : Performed by Yui Ninomiya .
: Managed by Glovision , with Masanori Tsuchiya serving as the Sound Director. Where to Listen The World S Finest Assassin Music
: A signature track reflecting the dual nature of Lugh Tuatha Dé. The main themes define the anime's identity and
and "For You" : Part of the core soundtrack ensemble. The World S Finest Assassin Music
: Included in the single Dark seeks light / Sanbunteki LIFE released by the Lantis label. Ending (ED): "A Promise" Artist : Performed by Aira Yūki .
: A version of "A Promise" is also sung by the character Dia (voiced by Reina Ueda). Background Score (OST)