They are both central figures in the tale Acallam na Senórach (Colloquy of the Ancients), in which they survive into Christian times and recount tales of the Fianna to a recently arrived Saint Patrick.
In Irish mythology, Cas Corach was a hero who helped Caílte mac Rónáin kill three werewolf-like creatures, the daughters of Airitech who would come out of the Cave of Cruachan every year around Samhain and destroy sheep.
The she-wolves liked music, so he aided in their slaying by playing a harp to attract and distract them and by persuading them to change to human form, while Caoilte cast a spear that penetrated all three, thereby killing them.
The 'Bodb Dearg', a god in Fianna time who is the son of the Dagda had a daughter called Scathniamh.
But they were forced to part from one another, and they never met again till the time Caoilte was old and withered, and one of the last that was left of the Fianna.