The Prophet emerges as an alluring, mysterious character for Season 2. He meets Michael and appears to Noma all in fire. Michael assumes that this man is the keeper/protector of Mallory for God and the townspeople. However, it is later revealed that the sacrifices from the townspeople are really benefitting Lucifer, a former angel that was defeated by Michael and Gabriel eons ago. This prophet, along with many others (maybe including Noma Banks), follow and are helping Lucifer to come back in living form, by trying to capture the Chosen One.
Personality
Being this man saved and cared for an entire town, he seems to be caring and a somewhat righteous man. However, it is revealed that he is working for Lucifer, an eons-long enemy to the archangels, especially Michael and Gabriel. He is also a deal maker; he let Michael bet his life for a card game that this man seems to quite enjoy. He also wants to take the life of the Chosen One to fully restore Lucifer to his body. This shows that this prophet is willing to kill to seek matters benefitting his own end and the one he serves: Lucifer.
After-Series Assupmtions/Conclusions
The Prophet may have been Lucifer's biggest ally if there were a season 3. He may have assigned Noma Banks the task of trying to capture The Chosen One, but she may have been unsuccessful a numerous amount of times against the archangel twins, Gabriel and Michael. He may have gotten sloppy when Alex, Michael and Gabriel forged a possible alliance, towards the end of Lucifer's defeat. One can assume that this Prophet would go down with his ship, a.k.a., Lucifer's final defeat.