Infernium: Nightshade Series #2 by Keri Lake

Pain is an abyss.

How naive of me to think I’d already reached the very depths of it when fate shook my world with a crushing blow. It turns out, there are fathomless levels of pain, like a winding labyrinth of doors leading to shadowy figures and long-forgotten secrets. The kind of inescapable descent into madness that twists nightmares into reality.

What lies at the end of this obscure path I have yet to discover, but where it begins, is a place called Infernium. An asylum, feared by those in Nightshade and untrodden by the angels who’ve forsaken its many lost souls.