BLOOD FEUD
Someone very powerful is trying to destroy Sorren and everyone he cares about. That puts Cassidy, Teag and Trifles and Folly in the cross-hairs, against an unknown enemy with strong magic and significant resources.
Sorren has spent centuries shutting down the plans of powerful immortals, dark warlocks and supernatural creatures, and now he's got to figure out which of those many enemies is out to get him before they pick off his friends one by one and come after him to finish an immortal vendetta.