Demon- Larry Stylinson

When debts are owed and there’s nothing else to pay with, why not pay with your only son? Demons accept that kind of thing right? When Harry's father owes money to a powerful demon, that is exactly what he does. But putting Harry in the middle of this the best idea?

Not caring Harry's father uses him to pay his debts to not just any demon but the king, but what would a king do with yet another useless human slave?