Blood Oath of the Stonefang

Through the primal nature of the Oath made by a member of the Stonefang Tribe to someone who has saved their life, an ability to protect the one who has saved them manifests. 

Protection of the Savior. If the entity whomst the oath was made is within reach and is targeted by an attack roll, you can use your reaction to take the damage instead (or halve it).

(optional) My life for Yours. During a short rest you can spend up to your constitution modifier of hit dice on the oath target. (possibly make it so if this is used you cant use hit die on yourself.)  

You can use Protection of the savior a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.