After he fought through the last of the militia, Batman located a tied up Gordon and was confronted by the Knight for a final showdown. Using stealth and deception, Batman managed to destroy all of the Cobra Tanks and faced the Knight head-on in a showdown with their vehicles. After Batman escorted Ivy to the tree, rejuvenated its roots, and protected both Ivy and the tree from the Arkham Knight’s Militia, Scarecrow played his hand and ordered the Knight (who had unveiled his true identity to Oracle as he guarded her), after he told him that the Cloudburst was fully operational, to disperse his toxin within the device. Batman entered his car and located one, final tree system to eradicate the toxin, that was hidden beneath the foundations of Gotham, rejuvenated its roots, and destroyed all of the responding militia tanks and drones that arrived to destroy the plant. After Batman subdued all of the militia that attacked the Clock Tower, Oracle was able to pinpoint Gordon’s location near Gotham’s bay just as Scarecrow ordered a full-scale assault on the GCPD.
After he finally revealed the location of Oracle at the same safe house and gas chamber that Ivy was previously imprisoned at, Scarecrow revealed that Oracle’s remaining time was limited. She was eventually retrieved from the safe house by Scarecrow and the Arkham Knight’s forces and brought to their base on Founders’ Island. As Scarecrow planned another attack on Gotham, Batman deciphered a message that was sent by Gordon, who tracked Crane down to kill him for taking Barbara and pinpointed the militia’s base to an underground subway station and mall complex that was previously under construction. Working together with Oracle, who was sent a vulnerability within the militia’s network (most likely from Jason) that enabled her to take control of the tanks and sabotage them, Batman was able to destroy the last of the army’s tanks and helicopters. Once there, Scarecrow interrogated Oracle, eventually threatened to test his latest fear toxin on her and gave a graphic description of its various symptoms, although he was forced away from her by the Arkham Knight, with the latter disgusted with his intention of interrogating her in that manner.
Ivy then used the last of her will and strength to amplify the ancient trees and destroyed all of the toxins with the pheromone, joker cosplay and tragically gave up her life in the process. Ivy revealed that the founders of the land that became Gotham believed in an abundance of nature and planted countless, massive trees. The oldest of those trees still resided within Gotham’s Botanical Gardens. Engaging Crane as he looked over the skyline, Batman was shocked when Gordon suddenly turned his gun on him, after he made a deal with Scarecrow for the life of his daughter, Barbara, who was still alive. If you want to breathe life into this character for upcoming Halloween, check out this Pennywise costume idea. Meanwhile, Batman visited Ivy at the GCPD Lockup and managed to convince her to help him destroy Scarecrow’s toxin, as all plants within the city and beyond would also be affected, by using her unique ability to control plant life. Told his long-time friend that he had everything under control. While Gotham was saved, the effects of Scarecrow’s toxin led to hundreds of deaths, with countless corpses littering the streets of the city after the toxin was cleared, as Scarecrow refused to surrender and assumed complete control over the remains of the Knight’s Militia.
In actuality, Oracle was still alive, with Batman’s account of her death a byproduct of the fear toxin in his veins as he looked at Barbara while she was held captive within the gas chamber. Reaching the safe house, Batman was horrified when he witnessed Oracle hallucinate from the fear toxin that was suddenly pumped into the chamber and seemingly committed suicide with a gun that was left on a table by Scarecrow to avoid further exposure. After he destroyed the tanks and took Barbara to the GCPD, Batman next learned that Scarecrow had ordered his forces to attack the Clock Tower to destroy her servers; without them, Batman and Oracle would be unable to locate Gordon again. After he dove head first into the cloud of toxin, Batman used the cell to energize the Batmobile once again with his mind slowly losing its sanity to Joker’s consciousness due to the effects of the toxin. As the Arkham Knight activated the Cloudburst, the chemical agents were released into the air, with the device amplifying their effects to the point that Gotham itself was covered in a perpetual cloud of the toxin and short-circuited the Batmobile’s energy supply.