To date, we know that at least three characters are set to appear in the upcoming prequel, Arkham Origins: Black Mask, Deathstroke, and obviously, the Caped Crusader himself, and from what little we know about the plot, plenty more of his rogues gallery are set to appear as well.
The current defacto Gotham crime lord is Black Mask, who is bankrolling a number of assassins, as well as a few of Gotham's boys in blue to take down the up and coming Batman. Over the last 70 years, the vigilante's list of enemies has grown extensively, giving Warner Bros. Montreal an extensive list of characters to choose from. With two Arkham games already featuring some of his more well known villains, their options have been reduced a bit. They'll want to go with villains that have some bit of familiarity and recognition, but who haven't been seen in gaming yet.
The following are some of the better options:
Lady Shiva - Women haven't had the largest role in the Arkham games, featuring only Poison Ivy and Catwoman to date.
Considered one of the finest martial artists in the DC Universe, this skillset also makes Shiva one of its deadliest assassins. While her time as a hired killer has put her on Batman's radar quite frequently, the vigilante is more than aware of her skill, having gone to her for training after Bane broke his back.
David Cain - Another of the Bat's rogues with enormous skill, Cain is an expert in virutally all forms of martial arts, small arms, explosives, and just about any and every way to kill a man.
He's also one of the many to have trained Bruce Wayne on his path to becoming Batman, and could be seen as a familiar face before ultimately revealing his true intentions to take out his former student. He would eventually go on to frame Bruce Wayne for the murder of one of his many romances, Vesper Fairchild.
NoBody - One of the lesser seen characters on this list, NoBody is one of the many anti-Batmans of the DCU. Whereas Batman captures and locks up the law breakers of the world, NoBody just kills them. Behind the arachnid like mask is Morgan Ducard, son of another of Batman's various trainers, Henri Ducard, who taught Bruce how to track people.
The two had something of a friendly rivalry until Bruce learned that Henri was actually killing his targets, instead of bringing them to face the justice of the legal system. By the time they meet again, Morgan has taken a new name, and comes at the Bat Family with an array of gadgets and skills that make him a match for Batman...almost.
Firefly - A pyromaniac in the purest sense, Garfield Lynns was able to turn his obsession into a job, becoming a professional arsonist. He wears an insulated battlesuit to protect him from the object of his obsession, and a jetpack to give him the same aerial capabilities of his namesake.
We had one of Arkham City's best boss fights ever against Mr. Freeze, where 'ol Bats had to use every trick up his sleeves. Might as well go to the other side of the coin, and have him go up against flame this time around. But with Lynn's jetpack, this fight could take place over a much more open area, and the pyrotechnics could make for some dazzling visuals.
Onomatopoeia - This is probably the Jersey in me, but Kevin Smith's Onomatopoeia is easily one of the more unique characters to have ever come out of the DCU. While there's an entire collection of villains who want to see big buffs like Superman and Captain Marvel put out of commission, Onomatopoeia goes out of his way to target regular human heroes. The character first targeted Green Arrow before setting his sights on Bats while under the mantle of the supposed like-minded vigilante Baphomet. He finally earned the Dark Knight's trust, only to slit the throat of Wayne's fiance, Silver St. Cloud, finally revealing his true identity, in a story arc Smith and "Comic Book Men's" Walt Flanagan have yet to conclude.
The character has a tendency of imitating noises in his surrounding area, hence the name. The habit comes across well on paper, and could make for an equally unique experience in a video game. Imagine tracking the villain, turning on a faucet, or knocking on a wall, just to get a sense of where he may be hiding.
KGBeast - If we're going back in time, might as well harken back to Soviet stereotypes of the Cold War era. Soda Popinski has nothing on Anatoli Knyazev, a well trained sociopath with a higher kill count under his hammer and sickle than Andrei Chikatilo.
He's a mediocre villain at best, but was truly dedicated to his craft, going so far as to cut off his own hand to avoid capture, armed to the teeth with the best hardware the evil empire had to offer. In the comics, he was little more than a tool of the Kremlin, but if Warner Bros. Montreal keeps the game in modern times, with the Soviet collapse, he could easily be motivated by a large sum of cash.
Prometheus - Everyone knows the origin of Bruce Wayne at this point, watching his upstanding, pillar of the community parents be gunned down at the hands of a lowly thug. Prometheus story is the exact opposite. His parents were Bonnie and Clyde-esque drifters, moseying from place to place, committing crimes, until they were shot and killed by police in front of their only son. While Bruce swore to take vengeance on criminals, Prometheus swore a similar oath against those who upheld the law. Taking his parents wealth, he too traveled the world, learning a variety of skills.
He wears a helmet connected to his brain and central nervous system, capable of downloading any type of knowledge as if he was Neo. But even without it, he's more than capable in martial arts, tactics, and intimidation, much like Batman himself. The sheer amount of ways that players would have to adapt to a villain capable of the amount of knowledge as the hero himself could make for one truly epic fight.
King Snake - Another consummate martial arts master, Edmund Dorrance was a former soldier of the British Army turned mercenary. At one point, he manages to take control of Gotham's Chinese triads, which could make him a possible subordinate of Black Mask's, or a potential usurper.
He also employs a mastery of stealth, which could make for a very intriguing boss fight against Batman. Furthermore, as the father of Bane. Snake's inclusion could make for an interesting look at a younger version of the muscled monolith.
Ubu - The bodyguard of the League of Assassin's Ra's al Ghul, Ubu is more of a title than that of a character, having been held at one time by Bane. This leaves Warner Bros. Montreal with an open template, leaving them to do almost whatever they liked with the character.
But more importantly, his introduction also serves as a great way of introducing the League.
