The Cult of Shadow Behind Us

You enter a large shrine with murals depicting battles against shadowy creatures. There's a stairway in the center leading up to a single pedestal. Upon which rest, the unmistakable shape of a single black key. You use Preserve Life again while we have a moment and restore my HP. As Yuta Ginae is kindly tending to her hero, you hear this time behind you sounds of movement. It seems to be a lot worse.