The black Ku school is devoted to the mastery of energy absorption. It is primarily pacifistic. The martial aspect depends on the student's ability to defeat an opponent or opponents by strategically forcing them to waste energy until they are unable to persist in their attack. Additionally it is possible to direct this energy back in such a way that it causes injury to the aggressor(s). The mastery of black Ku is by far the most difficult of the three schools, because of this it is also the most powerful, but due to its passive nature the least prolific.