Nothing is known of Ursa's origins, perhaps not even by him. He once painted a picture of his home for Darius, with mountains and caves. MacLeod suggested that Ursa grew up alone in the woods. Although he can speak, he does not talk much.

By 1634, Ursa was living in a cave in a French forest. The farmers of the surrounding villages took him for a demon, because they could not kill him. He was known among them as the "beast with no name."

Ursa, who had a strong feeling for the beauty of things around him, worked as a gardener at the Abbey. The monks learned of his immortality, but protected him as one of God's creatures and taught him to sing. Sometime between 1634 and 1789, Darius visited the Abbey of St. Gobain and met Ursa. Around the time of the French Revolution, the abbey of St. Gobain was demolished. Ursa fled to the catacombs under Paris. In 1993, he was still living in there.

Ursa is the only known immortal to the watcher's that uses a Scythe when fighting other immortals.