Dance Dark functions as the horse familiar within the Beast Knights organization. His assigned knight partner is Souichirou Nagumo, a former detective who acts as a protective figure for the younger knights. Dance Dark appears as a large brown horse. He maintains a serious commitment to his role as a familiar but possesses a distinct aversion to being ridden. This aversion manifested when Nagumo Souichirou attempted to mount him; Dance Dark threw him off, causing Nagumo to sustain a back injury.