Mechanical Guardians

Mechanical Guardians are robots found in the remains of Wonder City and seen in Batman: Arkham City and Harley Quinn's Revenge.

Arkham City Incident
While investigating the remains of Wonder City, Batman scans the memory of the guardians and discovers the secret entrance to Ra’s al Ghul’s sanctuary. During Protocol 10 the guardians were gathered up in a pile.

Harley Quinn's Revenge Incident
Harley Quinn acquired the Guardians and used them as her henchmen during her revenge plot against Batman. After Batman was saved by Robin, Harley unleashed them against Batman, but also took a sniping position on her Joker memorial to help in killing him. It should also be known that Harley painted them to look like Joker.