The line between heroes and villains isn't always clear. Someone committing a serious crime or offence may have good or noble intentions behind it, and someone doing a good deed might not always have the best intentions either. It's that kind of depth that can make a character all the more interesting and one of the best examples of this is the newest addition to the cast of Batman: Arkham City: one Mr. Freeze.

Dr. Victor Fries was an expert in cryogenics, searching for a cure for a disease his wife, Nora, was afflicted with. A freak accident one day left him extremely vulnerable to any temperatures above freezing, forcing him to wear a suit to preserve himself. Not only that, but he lost the funding for his work, which led to him turning to a life of crime in order to one day find that elusive cure for his wife's affliction. The tragic backstory makes him one of Batman's more interesting villains, which says a lot considering the Caped Crusader's rogues list includes characters like The Joker and Hugo Strange.

Rocksteady Studios and Warner Bros. Interactive unveiled the Mr. Freeze trailer for Batman Arkham City and it manages to capture the character perfectly. It depicts Freeze obsessed with his work and ordering Batman to help him find his wife, threatening to kill him if he doesn't. Not only that, but whoever did his voice did it perfectly, sounding very refined while also very threatening, especially when the helmet deepened his voice.

See for yourself how Mr. Freeze fits into the madness that is Arkham City.

httpv://www.youtube.com/watch?v=RAXcnYmu8_c

With the cast of villains continuing to grow and knowing the developers will be attempting to top Batman: Arkham Asylum in every possible way, Batman has his work cut out for him. The battle with Freeze appears to be some sort of stealth level, with Freeze using his cryo-gun to... well, freeze everything in sight, and it stands to reason that if players get hit with that, they're finished. The force field around him and those sensors that Freeze sends out won't be making things any easier for The Dark Knight.

With Mr. Freeze joining the fray, one can only wonder who else will make an appearance in Batman: Arkham City. With both returning faces such as The Riddler, and new additions including The Penguin and Solomon Grundy, many of the big names are covered. Who else could appear? Firefly? The Ventriloquist? Ra's al Ghul? They need to save some for the sequel to Arkham City, right?

Who else do you want to appear in Batman: Arkham City?

Batman: Arkham City arrives October 18, 2011 for the Xbox 360, PS3, and PC. It will also appear on the Wii U on another date.