Blood brother can refer to two or more men 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 idea being that each person's blood now flows in the other participant's veins.The act carries a risk due to blood-borne diseases. The process usually provides a participant with a heightened symbolic sense of attachment with the other participant.
Cultures
Scandinavia
The Norsemen entering the pact of foster brotherhood (Icelandic: Fóstbræðralag) involved a rite in which they let their blood flow while they ducked underneath an arch formed by a strip of turf propped up by a spear or spears. An example is described in Gísla saga. In Fóstbræðra saga, the bond of Thorgeir Havarsson...