For those of you who may not know, Demon Knights was one of the original New 52 series'. It was recently canceled. Personally, I think this was a great series, but it didn't sell enough. I am going to fan cast them and explain the characters.
Etrigan The Demon/Jason Blood
Etrigan is a rhyming demon from hell. Jason Blood is a human, they are fused together by Merlin. Blood can willfully summon the demon. They both have a complicated relationship with Madame Xanadu.
fancast: Sam Worthington
Madame Xanadu travels with Jason Blood. She possesses many magical powers. She is in a complicated romantic situation with Etrigan and Jason.
fancast: Gemma Arterton
Sir Ystin (Shining Knight)
Sir Ystin is a transgender Knight who joined the team by coincidence. This is one of the characters with the most depth in this series. Physically, Ystin is a female, but he identifies as male, and forces the other characters to acknowledge that.
fancast- Juno Temple
Al Jabr is one of my favorite characters in the series. He is basically a Medieval Tony Stark. This character is also one of the more heroic of the bunch and has the highest moral standards (and probably IQ) of all of them.
fancast: Johnny Depp (this will never happen)
Exoristos is the brawn of the group. She is an Amazon who was exiled from Themyscira.
fancast: I honestly have never been able to think up a good choice for Exoristos.
Horsewoman is a talented archer on horseback. She is very mysterious. Almost nothing is known about this character.
fancast: Isla Fisher
Vandal Savage is usually a villain in the DCU. But, during this period of time, he stops trying to take over mankind and joins forces with the rest of the Demon Knights to take down a few threats. He is probably the most fun character to read in the series.
fancast: Tom Hardy