He formed an alliance with Shredder and the Foot Clan, offering access to a Lazarus Pit if Shredder would contribute a large quantity of mutagen and build a mutagen-disseminating device to distribute it across Gotham. However, when Shredder failed to acquire a cloud-seeding device from Wayne Enterprises, Ra's al Ghul lost patience with his partner. To demonstrate the effectiveness of the ooze to Ra's al Ghul, Shredder mutated a League ninja.
Ra's al Ghul then broke into Arkham Asylum, killing several security personnel along the way, and made his way to the Joker's cell, where he obtained the formula for the Joker Venom. He ordered Shredder to pay the criminal with a canister of mutagen. In the meantime, he hired the Penguin to obtain the desired cloud seeder.
Ra's al Ghul and Shredder then fortified themselves in Ace Chemicals, where the mutagen-disseminating machine was completed and filled with both ooze and Joker Venom, which would cause mutation and madness among Gotham's residents. The Turtles and Batman successfully infiltrated the facility and fought their way past the two ninja clans. Ra's al Ghul expressed disdain that Batman had sent "children" to fight him, and battled Donatello and Leonardo simultaneously.
During the fight, he broke Donatello's arm and threw him off a catwalk, enraging Leonardo. The Turtle was initially unsuccessful in his fight against Ra's al Ghul, but was eventually able to disarm him. Ra's al Ghul was able to catch and break Leonardo's katana with his bare hands, before throwing the young Turtle backwards. However, Ra's al Ghul lost the fight when Leonardo kicked him in the groin, and then used a pressure point attack to render him unconscious.
- Ra's al Ghul's first name is not pronounced consistently throughout the movie. Most commonly it is pronounced "RAHz," but it is sometimes pronounced "RAYsh."
- Though it is not brought up in the movie, Ra's al Ghul is typically depicted as Robin's maternal grandfather.