The Yagyuu Family is an aristocratic samurai family that has been serving the Bakufu and Shogunate for many generations. They're family of generals and military leaders. Their expansive family estate is evidence of their immense wealth and their political connections. All male heirs in the family tend to be short.
As Amanto arrived, Kendo has been declined but a lot of people still go to the Yagyuu dojo to learn.
The Yagyuu Family is based on the real Yagyū clan. They were a family of daimyō (feudal lords) with lands just outside Nara, who became the heads of one of Japan's greatest schools of swordsmanship, Yagyū Shinkage-ryū.
The names of the 4 Devas are spoof of 4 girls in Strawberry 100% (いちご100%, ichigo hyakku paasento):
