Satan dispatched the demon Haroth (posing as an angel) to Barnabas, leader of a Jewish sect still faithful to Yahweh/ God of Abraham.
Haroth explains Jesus’s blasphemy of proclaiming the One God the true God, His repression of magic for the divine only and the dispersal of Yahweh via the Vyntari shards. Haroth then teaches Barnabas and his followers the art of Dark magic, something once reserved solely for demons.
Barnabas ultimately forms the Order of Haroth, a quasi-religious sect of Dark sorcerers. Their mission is to find the Vyntari shards and bring their god Yahweh back to prominence. They also swear to disrupt the works of the One False God as they call him, the god of Jesus and the New Testament.
The Order operates to this day through sorcerers like Dwyer Strathan.