Entei Tsukahara (炎帝塚原, Flame Emperor of the mound plain) is a former Royal Guard who is revered for having rebelled "The Blight", a massive invasion from Hell that attacked Soul Society, and later the World of the Living. He is notable for possessing a Zanpakutō revered as "the sword that comes every few centuries", Hiwamaru (火輪丸 Fire Ring), the flame counterpart to Hitsugaya's Hyōrinmaru.