This information, written in the style of a history book, formed some of the backstory for the Keita's Wings series.
Kieran Sclera was a counselor to the Muse king, Cato Pensier. In the year 145 he married the king’s young daughter Tracy. After a few months, Tracy disappeared into the neighboring kingdom of Merlandia. Driven by anger, Kieran joined forces with a Stygian called Adrian Blake. Under Adrian Blake’s tutelage, Kieran became a Stygian and killed his brother-in-law Crowther Pensier.