5. Joker – Batman: Arkham City
The Joker is perhaps the most recognizable villain within the Batman franchise, and the performance of Heath Ledger in The Dark Knight and his unforgettable presence in Batman: Arkham Asylum and Arkham City only added to the character’s legendary stature.
In Arkham City, Joker is instrumental in just about every criminal activity and instance of trouble that goes down behind the walls of the massive prison. Batman learns from Joker’s doctor that the unstable properties of the “Titan” formula are mutating in Joker’s blood, gradually eating away at his body and killing him. The Joker captures Batman and performs a blood transfusion on him, infecting him with the same fatal disease and forcing the Caped Crusader to find a cure for them both. What a d**k. Joker’s ability to make light of the most grave situations and to squirm out of almost certain peril makes him a truly infuriating, yet very formidable nemesis.