Note- Not that dark. But the tag was necessary.

Prince Blueblood is rich, handsome and stubbon. But he is one of the most important ponies in Equestria. He once gathered technology from all around the planet, intent on destroying crime in Equestria. With the princesses neglecting to anything about the situation, Blueblood must do it on his own. He is Batmane- The hero of Equestria. But he is not alone, he has a few allies. The Mysterious Mare Do-Well, and of course, Robin. And they have a long list of enemies to defeat. There is the Joker, a pony as crazy as Discord. It seems that he does have his biggest trick up his sleeve now...

Mare Do Well isn't any of the mane six.