Morgaine le Fey and her son, Mordred. she's after the Philosopher's stone. Dumbledore must have hidden it better after this attempt. she will use it's power to give recreate Camelot for Mordred to rule over. Batman calls in the League to help stop her.
we get to see Etrigan the Demon's origin. I think it's still pretty close to what it was in the comics, kind of consistent with Kirby's origin.