He is the Shield Anvil. Fener knows grief, so much grief that it is beyond his capacity to withstand it. And so he chooses a human heart. Armoured. A mortal soul, to assume the sorrow of the world. The Shield Anvil.
Verin's life, while not something RJ had mentioned, would now be my number one choice for an prequel, depending on how detailed RJ's notes about her are.