Madame Xanadu: Born in Avalon, sister of Morgan Le Fay and Vivian. Teacher of Merlin before their mutual betrayal. Later diviner for Kubla Khan in the actual city of Xanadu. Her longevity is due to being a Homo Magi and after besting Death in a game of cards. She can see the future and uses her ability to help people with various supernatural trouble. She's also played a centuries long cat and mouse game with the Phantom Strange. She's one of the few bi sexual heroes in the DCU and has had relations with both men and women. She's also had sexual relationships with John Zatara, Jason Blood/Etrigan and Spectre/Jim Corrigan.
I've been meaning to create this and the Phantom Stranger but kept procrastinating. I heard about Madame Xanadu but the first comic I read her in was 2011's JLD. It didn't leave an impression but then I read Matt Wagner and Amy Reeder's Madame Xanadu series and that's when I fell in love with the character. With JJ Abrams working on building their JLD universe, I hope they take a look at that series. It's exactly the kind of thing that's perfect for a tv show and introduce magic to a larger audience.