St. Ruvenheigen was a Church crusader who led a group of holy knights, persecuting pagans. He had flaming, flowing red hair with a full beard and an austere look on his face. His known weapons were a sword, shield, and spear. It is known that he was born during the winter, as this occasion was commemorated.
During his lifetime (approximately in his forties or fifties), he led his knights near Pasloe and came across Holo at night during the full moon. Denouncing her as a demon on sight he and his company charged at her, but having had enough of them, she simply changed form and drove them off. At the end, she left Ruvenheigen a particularly embarrassing souvenir of their encounter: a bite in the ass. She would recall it as being "sinewy and quite nasty."
The city of Ruvenheigen was later named after him. At the town market square, a statue of Ruvenheigen stands in battle-ready pose atop a tall pedestal. In the anime the figure is an equestrian statue instead.