Just as Thomas's breathing grew weaker and weaker, a loud bang came from the corridor outside the hospital room. Bruce was not startled in the slightest. Instead, an expression that said "I've been waiting for you" appeared on his face.
As everyone knew, Batman and Joker had another law: Joker would never let Batman die at someone else's hands.
Bruce had brought Thomas here and reduced him to this near-death state precisely so he could wait for Joker Martha to appear.
With a bang, the hospital room door was slammed open. When Martha appeared before him in Joker makeup, her face twisted into a crazed grin, Bruce's hand still clenched slightly.
Martha, who had burst through the door, froze as well.
The second Batman Joker aggregation law stated that the stronger Batman was, the stronger Joker became.
But what if there were two Batmen?
It was not an easy thing to verify, because when one Batman saw another Batman, he usually only said, "Get out of my Gotham," then did everything in his power to make those words a reality. The odds of the two appearing in the same frame were practically zero.
Yet Bruce had long inferred the answer from past experience. Gotham had once had two Jokers—Schiller and Jack. So whose strength did Batman's strength change in response to?
The answer was Schiller.
And now Bruce's Gotham had two Batmen—Bruce and Thomas. So whose strength did Joker Jack's strength change in response to?
The answer was Bruce.
From these two examples, it was not difficult to conclude that a Joker's strength changed alongside the Batman with whom he had the deepest bond. In other words, even if Bruce and Thomas appeared together now, Joker Martha would only change according to Thomas's strength, because they were husband and wife