The Fiery Spirit series of items was introduced in version 2.0 of Honkai Star Rail, and if you've reached the Luofu's alchemy commission, you can start farming them before arriving on Penacony.

Fugue is a 5-Star Fire character of The Nihility path ... For Fugue, you need to use a lot of Fiery Spirit and Immortal-based materials to fully upgrade her capabilities, and in total, to upgrade ...