Mr. Freeze

The only man with the cold, cold heart in Gotham, it is Mr. Freeze!

Real Name:  Victor Fries

Arkham Origins: Mr. Freeze does not appear in the Main Story, but if you buy the DLC pack, (called Cold, Cold, Heart) You can see and fight Mr. Freeze.

Arkham Asylum: He does not appear in the game, but after a fight with Harley Quinn, you can look around the room, and you will find his asylum cell.

Arkham City: After you give Mr. Freeze the cure, he backstabs you and you end up fighting him. After you are done, you get the cure, but find out Harley Quinn snuck in and stole it.

Arkham Knight: It is unsure that Mr. Freeze will be in the game.