Blood siblinghood is a Barashin custom common to many cultures and species. Would-be blood siblings adopt each other as such via a ritual that involves cutting their hands, claping them to let the blood mix, and reciting a pledge to each other. This ritual is believed to have originally held magical properties, but that knowledge has been lost. Blood siblings do not bear any special relationship to each other's biological family, relatives by marriage, or other blood siblings, only to each other. There is no way to formally dissolve a blood sibling relationship, but like any brothers and sisters they may not stay in touch or acknowledge each other if they should drift apart or have a falling out.