Blood Pact

Haldune is living every father's nightmare: his son Carid has been kidnapped. The kidnappers don't want money; they want Haldune to sit down, shut up, and forget he ever saw anything.
The only problem is, Haldune can't forget. He knows what he knows, and he's got a demon in a bottle to prove it. Haldune must engage in a terrifying race against time to rescue Carid before the kidnappers decide the boy has outlived his usefulness.
Haldune once served as a steward for a mysterious order known as the Disciples, unaware that their seemingly benign scholarly pursuits masked an unholy dabbling in demonic magics. Then he discovered their latest creation: the Bloodshade, a slave-demon tied to a bottle.
The Bloodshade can make her master intangible, invisible, and can transfer his wounds to other people. Unfortunately, her powers require human blood as fuel. And worse: every so often, and she takes over her master's body for hours or even days before her strength fades again.
Dealing with demons is forbidden both by the Church and by the College (where students are trained in the sorcerous Art). When Haldune first learned what the Disciples were really up to, they took Carid to shut his mouth. So Haldune has taken a path they did not expect: he stole the Bloodshade's bottle and vanished.
The Disciples can't hold Carid over Haldune's head if they can't find him. But Haldune knows he can't free the boy on his own...