The Heart, Dishonored Wiki

The Heart is a mystical object the Outsider gives to Corvo Attano to assist him throughout the events of Dishonored, and to either Corvo or Emily Kaldwin to help them in Dishonored 2. A vessel designed to contain a spirit, it is used to help uncover runes and bone charms hidden throughout the Empire of the Isles. It starts beating and lights up when turned toward supernatural objects in the area, and beats faster as the protagonist gets closer. In addition, when one squeezes the Heart, it whispe

Flesh and Steel, Dishonored Wiki

Just did a quick 3D render of the Outsider's Mark! : r/dishonored