notes that within the game's actual story, the character Arkham Knight (Jason Todd) underwent his own "training" under Deathstroke to become Batman's equal in martial arts and tactics. Alternative "Cheats" (Non-Trainer)
Several side quests (like The Perfect Crime or bombing diffusions) have hidden timers. The trainer can pause the internal game clock, giving you infinite time to solve puzzles or disarm bombs. Batman Arkham Knight 1.6.2.0 Trainer