Stigma of the Sinless

Stigma of the Sinless (罪なき少女達のスティグマ) was a story event in Assault Lily: Last Bullet, starring Legion Hervör. It ran from March 31, 2021 to April 16, 2021, and was rerun in July 2022.

Translation
The complete English translation of Stigma of the Sinless can be found here in Google Doc format.

There is also a full set of subtitled YouTube videos by GEHENA Subtitle Labs.