According to a teaser released on the game’s official Facebook page.
Earlier today Warner Brothers announced that they are issuing a new DLC for Batman: Arkham Origins, which has been expected of them for some time now. Based on an image posted on the game’s Facebook, the DLC will very clearly feature the classic villain, Mr. Freeze.
This is further substantiated by a DC Animated Universe Wiki page which reads:
“As Bruce is leaving, Boyle comments that he is to be presented with a humanitarian award. Posing as a security guard, Batman sneaks into Gothcorp’s offices and finds a security camera tape with footage of the accident: on it, a man named Victor Fries records that he has put his wife, Nora, into cryogenic stasis after she became terminally ill, to give himself time to research a cure.”
This plot line follows very closely to the classic Mr. Freeze Batman plot line, which further confirms that he will be the main villain in this DLC. This will be Mr’ Freeze’s first appearance in the Batman: Arkham series.