Hamon

A technique for fighting vampires and zombies. Usually utilized by crusading knights of the Purple Kingdom. Most of the holy men of the Church use Hamon to some extent. Some extended families in the Purple Kingdom practice Hamon, and pass down its techniques through generations. Some temples in other more eastern civilizations teach Hamon during these medieval times (5th century).
For more info, see the JJBA wiki:
https://jojo.fandom.com/wiki/Stand