Mark Cheung (Earth-5192)

Mark Cheung is a former Ace Chemicals factory worker who works on the Ace Chemicals Factory. When the plant was attacked in October 31st, 2015, Cheung and his fellow employee Adam Brewer were the only survivors of a raid by the Arkham Knight, but were then saved by Batman.

Scarecrow's Revenge
Mark Cheung worked as an employee for Ace Chemicals at the Ace Chemicals Factory on Bleake Island, Gotham City. During a normal day at his job, the factory was attacked by the Crimson Militia under the command of the Arkham Knight and Scarecrow.

Together he and five other workers, including Adam Brewer, were made hostages by the militia members. However, only Cheung and Brewer were spared when the mercenaries realized they knew the most about Ace's systems among the employees, as they planned on granting Scarecrow access to the fusion chamber.

Rescued
The same night, Cheung was saved by Batman after being brutally beaten by three militia members; the Dark Knight had infiltrated the factory in search of survivors and means to locate the militia's main hideout. After questioning Mark about the whereabouts of Scarecrow, he was confronted by the Arkham Knight, but Batman managed to keep Cheung safe.

He took both Mark and Adam to the Batmobile, automatically setting the vehicle to take them for safety with Commissioner James Gordon and other GCPD officers who awaited outside the facility. During the rest of the night, Mark and Brewer were kept safe at the GCPD Headquarters. When the place was attacked by vengeful forces of the militia, he and Adam kept hidden in the corrections room alongside all other survivors still in the city.