Fey Trickery

As a descendent of the Seelie of Feywild, you have the power to form contracts with the backing of Fey magic. Whenever you make a deal with another creature it is magically binding provided there is some official sealing of the deal (handshake, blood pact, contract, etc.). Both you and the other creature act as if you were under the Geas spell. If either takes direct action against the terms of the contract, they take the 5d10 psychic damage each time they take direct action against (or once per turn in combat). If one side of the contract is fulfilled they are no longer under threat of Geas. If you plan to use syntactic tricks, make sure you, the PC, or the DM writes down the wording.