[Karlach laughs again, a deep bark of rough anger, though she doesn't pull back. With the hand that isn't holding down Clarisse's knife arm, she reaches up to bang on her chest with a fist. Though there's no ring of anything metallic, her chest glows brighter. Hotter. It sounds sharp. The flare of it backlights her ribs, shines in her eyes to give them an unnatural glow.]

Lyrium device for a heart. Courtesy of Zariel.

She can't stand the thought of anything squirming out from under her thumb, but this is what she wants. Her little experiment.