The character Constantine made a brief appaerance in Arrow which made me interested in his character. Netflix never did get the show online and the DVDs are never available but I found the entire series on cwseed.com. In only ran for one season and did not get a conclusion, we only get a disturbing revelation about one the main characters. A revelation I wasn't surprised about, I was expecting it actually.
Anyhow, John Constatine is a modern day mage, He uses magic to battle demons and other evils. He's warned by "Manny" apparently his Guardian Angel that Darkness is coming. Something or someone is weakening the boundaries between Earth and Hell. John doesn't like to let people get close to him because those who do tend to end up dead. And he blames himself.
John's friend Chaz Chandler has the ability to come back from the dead, explained over the course of the series. But otherwise has no magic powers. He puts himself in harms way knowing he will come back even if he's killed.
Zed Martin (not her real name) is a psychic who before she met him has dreams about Constantine and draws pictures of him. He reluctantly accepts her help, eventually. Zed is hiding from her mysterious past. And not sure if her visions are a gift from God or a curse from the devil.
Manny is an angel who most of the time only John can see. He claims not to be allowed to act directly in human affairs. He appears most often by temporarily possessing humans so he can talk to John. He usually returns the people to normal in the middle of a chat which annoys John because they don't know what he's talking about.
In the final scene its revealed that Manny is in fact in control of the evil forces trying to bring Hell on Earth. I was expecting something like this because I know 2 Corinthians 11:14, which says that Satan (called the First Fallen in this show) disguises himself as an angel of light. How better to keep an eye on a demon hunter than to pretend to be his guardian angel. This revelation would seem to change Manny's answer when Zed asks him if her visions come from God or not and he says "I'm here aren't I" shes under the impression that means they are from God.