Kildare's cousin Gwyinnion, often referred to as "Mad Ginny" was driven to insanity in the age of iron and steam after surviving a brutal attack and rape by a Dark One in the English town of Cottingle. She is a sad, delicate and profoundly damaged soul, and Kildar makes it a point to look after her.

The attack in Cottingley left her pregnant, and she gave birth to a son who was used as a vessel for an ancient evil known as the Dark One. Along with her cousin Kildare, Gwynnion stopped the Dark One. Stopping the Dark One did not heal Mad Ginny's broken spirit, but it did give her some peace of mind.