Altered Blood

A holy blessing carried in your heart, an alchemic experiment that changed your biology, an infernal pact that replaced an organ, or a curse from beyond the veil that lingers in your veins. Regardless of it's source, when blood is drawn from you, it does more than coat blades. General Idea is for Players to select an option that infuses their blood with radiant, necrotic, or any elemental damage type. They gain a resistance to the damage type, a reaction to do damage and give a debuff  when they are attacked, and a once per long rest ability to make a weapon magical and do extra damage. I used Martyr's sacrifice as the blueprint, and will post two options to convey the idea.