Bull Inuzuka is a large, intelligent ninken (ninja dog) and a loyal companion to Kakashi Hatake in the Naruto series. Recognized by his imposing size and stoic demeanor, Bull assists Kakashi and the other ninken with reconnaissance, tracking, and combat support. Despite his intimidating appearance, Bull is gentle and reliable, often serving as a steadying presence among Kakashi's pack. His unique ability to communicate and cooperate with shinobi makes him an invaluable ally throughout various missions in the series.