I've long been a fan of Black Mask from Batman.
One of the issues I have always had with Batman is that he has arguably the most impressive rogue gallery top to bottom in all comics, but most people only focus on a key few. By no means am I saying that an iconic genre defining villain like The Joker should be cast aside, I'm not (that) stupid. There are so many great baddies for Batman to go toe to toe with though and more often than not, we usually get Joker, sometimes we get Bane and Two Face and on occasion we get Scarecrow, Riddler, and Poison Ivy. Throw Catwoman in when they want a romance subplot.
When I discovered the original Black Mask (Roman Sionis) I instantly fell in love with him and wondered why he wasn't featured more. This is a guy who grew up with Bruce Wayne, his parents being rich socialites themselves. The difference was that they hated the Wayne's and had a poor relationship with their son. While Batman lost his parents in a tragic accident at a young age, Black Mask killed his parents and made it look like an accident to take over the family cosmetic business. While Batman has a very good business acumen, Black Mask has almost none, running his family business into the ground. When Bruce offered him a bail out in exchange for him stepping down from his CEO position, he lost it and broke into the cemetery his parents were housed him and smashed his father's ebony coffin to pieces, which he used to fashion his signature mask. He wears the mask because he resents the mask his parents wore to maintain their standing in society and claims we all wear masks to conceal our true selves.
One of the other things I like about Black Mask, is he doesn't have any actual superhuman power. He is just a ruthless, sadistic, son of a bitch who will stop at nothing to take over Gotham. Hell, at one point he did. He was actually the first criminal to have complete control over the city.
He isn't adverse to forming a strategic alliance here and there, but he is always out for himself. When Raus al Ghul freed the inmates at Arkham, he stayed behind, because he didn't want to fall in fine with Joker on some personal vendetta against Batman. He was his own man and I like that. Yeah, Batman is a constant thorn in his side, but he is more concerned about regaining hit foothold in the criminal underworld and not with half assed revenge plots.
If I wasnt on mobile, I could argue how if Black Mask would have come around twenty years earlier, he would be the iconic lead villain in the series. He has all the qualities fans love about Joker, minus the obsession with Batman and the abusive controlling relationship with Harley.
Sadly, we was one of the few comic character who was killed and written off for a long time. Catwoman, a constant target of his threats, shot him through the face and killed him, until he was eventually (and fittingly) reseruccted as a Black Lantern.
Things are looking up for him in terms of gaining some mainstream footing. He is rumored to be one of the main villains in an upcoming film. If they can stick to the central themes of the character, use the original and not the Jeremiah Arkham version, and people can see he isn't just a Joker knockoff, then I think this could help propel him to the forefront he deserves.