In the series Edit
Yvo was first met by Silaqui, Einkill Ungart, and Grigore Ardelean in his home, Snowcreek Manor, when they came to discuss the matter of the town's centipede infestation. He denied the existence of a major problem, but told them that he wouldn't stop them if they assisted the guards with anything that came up, before having them escorted out.
He wasn't seen again until after the defeat of the Very Hungry Centipede, when he and a group of guards came to arrest the party for the suspected murder of his servant Tharvin Durret and the suspected kidnapping of his son Jakois Mustele. After a few minutes of confrontation, Nuul jumped out from the shadows and held a dagger to Yvo's throat to threaten him into letting the party go. Amales Mustele's readiness to yield to Nuul's demands angered Yvo, and he slit his own throat against Nuul's dagger to stop him. Afterwards, Nuul escaped and Amales demanded that the party leave the town immediately.