I took this description from elsewhere but it's quite a concise blurb:
The story is set around 1910 (give or take a few years). Every year, Lord Nicola A. Bradherley, one of Europe’s leading aristocrats, sends his coach round to various orphanages to adopt little girls and trains them to join his opera troupe. But most of these girls never make it onto the stage — a far more sinister fate awaits them, sacrificed in the name of the greater good.
I bought it at the age of 14 or 15.
It kind of damaged my mental health...
Especially the part where the guy who gets
burried alive killed himself with a fucking pen. He rams that god damn pen into his fucking artery in his neck.
It got me into whatever this genre is called. It was the first time an MC was actually very believable to me. Ana satsujin and abnormal kei joshi are trying to bring it back , but it's just not the same