An Oath is a vow or promise made strongly by a practitioner, one that cannot be broken without dire consequences. Different from a simply lie costing the practitioner a bit of power, breaking an oath causes a huge backlash against the one who does it and can possibly lead to the practitioner being Forsworn.
The oaths listed here are those in the story which are explicitly referred to as oaths or promises, as opposed to statements which could potentially be construed as oaths.
- In Bonds 1.4 Laird Behaim asks Blake to leave Hillsglade House for a walk to talk with him about his new situation. In order to reassure Blake that he isn't tricking him in some way he promises that he will provide protection while Blake is in his company, and that he will return him to the house unharmed provided it is in his ability to do so. He also promises to smooth over legal issues that has arisen over the murder of Molly Walker - "I’ll make this as stress free for you as I can. Nobody will enter the house, if I can help it, which I can. I promise you this."
- In Bonds 1.x Rose Thorburn Senior writes that she swore an oath during an argument with her father to never make her children go through the struggles of the life of a practioner - "I swore I wouldn’t ever make my children go through this. I would let them lead lives untouched by all of this."
- In Damages 2.3 Rose promises the ghost June Burlison that if she agrees to be bound then Blake will keep her warm to the best of his ability. “If you agree, I guarantee you my partner in the circle right there will keep you warm as best as he can.”
- In Damages 2.4 Ms. Lewis promises that should she or any of her partners be going to maneuver Blake into a corner to force him into their service then they will look him in the eye and explicitly state exactly what they are doing. "We’ll tell you before we maneuver you into a corner...I or one of my partners will look one of you in the eyes and inform you exactly what we’re doing, when it comes up.”
- In Damages 2.4 Ms. Lewis promises that she will assist them in leaving the house to deliver a letter, saying that she will see them safely out and back to the house and guaranteeing no tricks or traps until she next meets them.
- In Damages 2.5 Letita says she will make Blake pay for calling her a coward.
- In Damages 2.6 Maggie Holt first mentions that she has promised her parents that she will attend school.
- In Damages 2.x the powerful goblin which destroyed Maggie's old home forced her to agree to experience blood, darkness, and fire three more times in exchange for allowing her and her parents to live. "You’ll experience what you experienced here, twice more. The rule of three, to make this stronger. Perhaps it will be me again. Perhaps no. But you will experience blood and darkness and fire, like you experienced it here. If you agree, it will be so."
- In Breach 3.1 Blake swears to help Rose leave the mirror world. "I hereby swear that I’m going to help you, in exchange for your loyalty and support. We’re going to find a way to get you out of that mirror world. I will make sacrifices if I have to, short of actually standing by to let any transition happen. I so swear, to you, and to anything that hears.”
- In Breach 3.1 Rose swears to help and protect Blake. "I will help you. I will do what I can to protect you from whatever’s going on with you, good or bad. I swear.” She also swears that should something happen to Blake she will pass on word of it to his friends. It is later revealed that neither of these oaths were binding, as Rose had not awakened at that point.
- In Breach 3.2 Blake swears to investigate the possibility of moving the house and all things of importances within it to a different location in exchange for being allowed to leave the Briar Girl's presence alive and unharmed. He also swears, in exchange for knowledge, to try to give the Briar Girl a patch of land in the area around Hillsglade house or an equivalent other form of payment if it is not possible.
- In Breach 3.4 Blake promises Leanne that he will show her what's wrong later if she keeps his secret when she notices his glamour start to break.
- In Breach 3.x the faerie ambassador promises to Sandra Duchamp that for 8 hours all may leave his realm without any retribution of any type from him or caused by him.
- In Breach 3.x Jeremy Meath promises to Sandra that he will prevent Blake's return to Jacob's Bell after Blake departed for Toronto.
- In Collateral 4.2 Blake promises to not say where he is from to the leaders of Toronto.
- In Collateral 4.2 Conquest swears that he will not damage Toronto, Jeremy, those Jeremy is responsible for, or the Duchamps in return for Jeremy granting him one future favour and sitting out the conflict over Blake and his knowledge.
- In collateral 4.3 Blake and Rose agree to try to do Conquest three favours over the course of three days. They will bind and return to Conquest Pauz, the Hyena, and Ur in any order, one per day.
Due to the manner in which Blake was removed from the world by Ur all oaths he made, and all oaths made concerning him, were dramatically weakened. Blake is no longer bound by any oaths he made prior to the end of arc 7. Also, Jeremy is not made forsworn, despite breaking his oath to prevent Blake's return to Jacob's Bell, and does not appear to have suffered any significant loss of power.