Talk to Karn | The Tears of the Mountain Darksiders 2 Guide

You can find Karn in the north-western part of [Stonefather's Vale]. Depending on preferences, you can go there on foot, through Tri-Stone's north exit, or by opening the world map and fast travelling. No matter the choice, go to where the screen shows. It will trigger a conversation with Karn.

[TIP: Don't forget to exhaust all topics; thanks to that Karn will give you another side quest [Lost and Found Part 2]].