We don't know much of him. What we do know is he is the father of Swiftkill and Bloodspill, and former member of the Elite Guard. It is unknown whether or not he is still alive, or if he ranked Swiftkill in any height.
Depicted below to the right is art of "Yuna", said to be Banehollow's wife. It is not confirmed by KayFedewa if Yuna is canon, but Banehollow is.