Blood Oath

Blood Oath Magic  ( けつえき めいやく,   Ketsueki Meiyaku ), is a  Caster-Type Magic  that involves implementing magic into the act of a blood oath,  when a pair or group of person would shed blood through cutting their hand with a sharp object or tool and then proceed to shake hands in mutual agreement with/to a task they swear to uphold. Typically, betraying this newly formed 'mutual trust' is taboo and has extremely severe consequences. This is a magic that is well known among dark mages and is utilized in order for both sides to come to a mutual consensus in regard to a situation or act, sometimes needing to bear results in order to satisfy the deal.