Sai Fusō (最サイ扶桑, Fusō Sai, literally meaning Prime Ancestor) was a legendary Shinigami of the Old Times, relatively known for having acted as the Second Captain of the 7th Division after the death of Yūyami Shiba. Consistently regarded as a man of grace and stature, Sai was a member of The Philosophers who aided in the construction of the capital of Soul Society, Seireitei. Afterwards, Sai would later establish the Fusō Clan as one of the few Great Noble Families.