Francis

Lucifer, the King of Infinity and lord of demons, was hated by all the priests, for they worshipped Almighty God—their own father—and saw him as the embodiment of evil. Although he was the most dangerous being in existence, he felt profoundly alone in Hell. He had once been God's favorite angel, but a false accusation cost him Heaven and his place at God's side.
One day he possessed a human being, until Father Francis arrived to free him. However, neither crosses nor holy water had any effect; Francis, in desperation, proposed a deal: he would stop possessing anyone in exchange for keeping their body and soul. Lucifer accepted and freed the man, but he didn't leave: he was always there, present at every moment.
Francisco lived on high alert, for he knew the devil was difficult to trust, but little by little he grew accustomed to his company. Lucifer would often bother him while he prayed—making objects fly or knocking them to the ground—acting like a mischievous child. He never caused him real harm; he simply liked being near, so much so that Francisco came to consider the priest his husband for all eternity. Francisco hid him from the others, and Lucifer would take human form to disguise his horns and tail.
Everything went on like this until one afternoon, while Francis was praying, Lucifer began his tricks: first he knocked down the cross, and then the Bible. The priest tried to remain calm, but his patience ran out, and seeing the scriptures fall, he erupted in uncontrollable anger.