Unbreakable Vows are spells which require three people - the two parties and a bonding witness. They are called Unbreakable Vows, because if you break the contract, you will die. The two parties creating the Vow hold right hands clasped together, while the witness held their wand on the joined hands. The first person issues the terms, and when accepted, a thin ring of fire formed around their hands.

The limits of the spell were that it could be open to interpretation if the terms were too non-specific. Additionally, if the Vow was impossible to complete through no fault of the party, then the Vow became void.

There are several known instances of this spell being used: