SPOILER WARNING: This article contains major spoilers for "Crisis on Infinite Earths, Part 2," the second installment of this year's Arrowverse crossover.
"Crisis on Infinite Earths" just put the "Dark" in Dark Knight. In "Part 2," the second installment of the massive Arrowverse crossover, Batwoman and Supergirl discovered that Earth-99's Batman killed the Superman of his world.
After he gathered the heroes on Earth-74's Waverider, the Monitor explained that he sought several paragons to help defeat his brother, the Anti-Monitor. Two paragons were already on board: Sara Lance, the Paragon of Destiny, and Kara Danvers, the Paragon of Hope. He sent the rest to search for the Paragons of Truth and Courage, with Superman, Lois Lane and Iris West-Allen seeking Truth and Kate Kane and Kara searching for Courage.
This led Kate and Kara to Earth-99, where they met an aged Bruce Wayne played by Kevin Conroy. While Kate caught up with her cousin, Kara hung back with his assistant Luke Fox. Luke showed off Bruce's trophies: the souvenirs he'd taken from villains he'd killed, like Riddler, Doctor Freeze and Joker. Among them, Kara spotted a pair of glasses, cracked and spattered with blood.
"Those belonged to Superman -- his alter ego, at least," Luke explained.
"Bruce killed this Earth's Superman?" Kara asked, horrified.
"Who do you think put him in that exoskeleton?" he replied with a smirk. "Big mistake."
Meanwhile, Kate joined Bruce in the Batcave. She tried to convince him to join them, in an effort to save other worlds from dying, but he simply said, "Well, if they're anything like this world, maybe that's for the best... There was no hope for this world."
At that, Kara burst into the room wearing her super suit. "This guy's not a paragon of anything," she spat.
"What did you do?" Kate demanded.
"Clearly, what you couldn't," Bruce retorted.
"How was he a threat?" she continued.
"Strange visitor from another planet comes to Earth with powers and abilities far beyond those of mortal men?" he hissed. "Clark. Clark always said yes to anyone with a badge or a flag. He gave them too much power. My parents taught me a very different lesson: life only makes sense if you force it to."
With that, he pulled back his fist and punched Kara, sending her flying across the room. The gauntlets on his exosuit glowed green, revealing the Kryptonite inside. "A little souvenir from the old home town," he explained, while Kate shielded Kara with her body. "The Kate I knew didn't trust anyone, let alone a Kryptonian."
"I don't know what happened to you, Bruce, but it ends now," Kate said.
"Yes," Bruce agreed. "Let it end. Let it all end. This world's not worth saving in any universe."
"If you really think that, you're going to have to kill one more person: me," she insisted, standing between him and Kara.
"Don't be a fool," he retorted, swinging at her. She grabbed his arm, blocking him, and kicked him in the chest. The blow sent him backwards, so he hit a metal table with his back. The exoskeleton snapped, sending an electric current through his body. She stepped forward to help him, but Kara held her back, pointing out she would die as well if she touched him.
"Kate, listen to me," he gasped. "There is no hope." With a sigh, he breathed his last and went limp.
Defeated, they returned to the Waverider. "Bruce Wayne wasn't a paragon of anything," she said.
"Batman tried to kill Kara, and now he's dead," Kate added with a tight smile. "So we're doomed."
The Monitor insisted there was still hope. With that, Ray Palmer booted up his paragon detector, which flagged the ship as the last location of the Paragon of Courage.
"Your machine works just fine," the Monitor said, revealing that Kate had been the paragon all along. "I said the path to Earth-99 would lead you to the paragon, and that has come to pass. You are the Bat of the Future, Kate Kane. You are the Paragon of Courage."
"Crisis on Infinite Earths" continues in The Flash on Tuesday, Dec. 10 at 8 p.m. ET/PT. After the winter hiatus, the crossover will conclude on Tuesday, Jan. 14 in Arrow at 8 p.m. ET/PT and in DC's Legends of Tomorrow at 9 p.m. ET/PT.