Collateral Soul

A specialized spell that allows those characters bound to a demonic patron the ability to collect souls for their masters. The caster after casting this spell on a written contract and with a bit of the targets blood can then bind the targets soul to said contract.  If the contract is not fulfilled or terms are broken the targets soul can now be collected upon his death, and then damning it for eternity in servitude to the named devil. The death of the target that is in breach of contract can be up to the casters imagination as long as the caster deals the killing blow.

Additional Targets can be add to a contract at higher levels 

5th level(2 targets) 11th level(3targets) 17th level(4 targets)