Blood brother

Male not related by birth who has sworn loyalty

Blood brother can refer to two or more people not related by birth who have sworn loyalty to each other. This is in modern times usually done in a ceremony, known as a blood oath, where each person makes a small cut, usually on a finger, hand, or the forearm, and then the two cuts are pressed together and bound, the symbolism being that each person's blood now flows in the other participant's veins.

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