Known by names such as chi, chakra, or countless others, ki is a supernatural life force which is contained within all living beings, be they plant, animal, or humanoid. While many warriors learn to utilize ki to generate spectacular powers, none have mastered its use like the esoteric, whose understanding of ki is matched only by their strict training regimen. Through intensive training, an esoteric can harness their ki using a variety of disciplines to create techniques all their own.
Esoteric come from all walks of life. Some are warrior monks who meditate and practice in secluded monasteries. Others utilize their spiritual powers to accomplish all manner of clandestine activities on behalf of mysterious ninja clans. While others yet, are wandering martial artists who travel to foreign lands looking for those skilled enough to challenge their strength or prove a worthy inheritor to their fighting discipline. In any case, esoteric all share a mastery of ki through vigorous training, and the development of unique fighting styles.