Mycroft was involved in a skirmish at the Ice Fangs where he killed Strix Hurthwell, the mate of Strix Strumajen and father of Strix Emerilla. He carried off his head and settled in the Ice Narrows where Kreeth, the arch hagsfiend, also resided. He managed to sway her puffowl into serving him and used him to steal Kreeth's formulas and spells. Mycroft promised him he would transform Puffowl into either an owl or a puffin. His treachery was revealed when Kreeth was searching for a feather for her changeling, Lutta.
Kreeth found out from another hagsfiend that Mycroft had killed Hurthwell and settled in the Ice Narrows. Kreeth used her divining eyeball to discover where Hurthwell's head was but also discovered her own formulas present in his dwelling place as well. She immediately condemned the puffowl who had by that time fled to Mycroft. However, she eventually managed to sneak into Mycroft's dwelling place and steal a feather from Hurthwell's head.