Hugo Strange figures out Batman’s identity in Arkham City through detective work, not a single magic reveal. He studies Batman’s behavior, builds a psychological profile, and connects the pattern back to Bruce Wayne; later materials and fan discussion also point to his broader surveillance and analysis of Batman over time.

How he likely did it

  • He monitored Batman closely and treated him like a case study.
  • He compared Batman’s habits, timing, and access to a pool of possible suspects.
  • That process led him to Bruce Wayne as the most likely match.

In-story context

Strange is written as a master manipulator and psychiatrist, so the reveal fits his character: he wins by observation, profiling, and patience rather than brute force. The game does not spell out every step in a super-detailed scene, which is why it can feel a little abrupt.

Simple version

He basically profiled Batman until the evidence pointed to Bruce Wayne.

TL;DR

Hugo Strange deduced Batman’s identity by studying his movements and psychology over time, then linking Batman to Bruce Wayne.