SPOILER WARNING: This article contains major spoilers for "The Wrath of Rama Khan," the midseason finale of Supergirl.
The Monitor has picked up another recruit for "Crisis on Infinite Earths." In "The Wrath of Rama Khan," the Supergirl midseason finale, he chose the Martian Manhunter himself J'onn J'onzz for the battle to save the multiverse.
While Supergirl fought Rama Khan to stop his plan to destroy humanity, J'onn reconciled with his brother Malefic. As a result, Malefic helped the DEO stop Lena Luthor's Project Non Nocere. Since she modeled the project after his Q-waves, he was able to counter them with his own mental ability. After Malefic successfully stopped Lena, J'onn sent him home to Mars to join M'gann and restore peace to the planet.
Once Malefic was on his way, the Monitor greeted J'onn. "Well done, J'onn Jonzz," he boomed with a smile. "You passed the test."
"Test?" J'onn said, then realized, "You released my brother from the Phantom Zone. You brought my brother here?"
"When I saw you fight in Elseworlds, I could see that you were a great warrior, but one plagued by his past, and that made you vulnerable," the Monitor explained. "You believed it was because you had left Mars, but it was something far, far greater, J'onn. Your brother. But now that you have faced those demons, you have come to learn your vulnerabilities are your strengths, and now you are ready."
"Ready for what?" J'onn demanded.
"A crisis," the Monitor replied, referring of course to next week's "Crisis on Infinite Earths" crossover event.
Malefic made his Supergirl debut in the Season 4 finale. In the episode's stinger, the Monitor ushered him into National City. He told Malefic he could exact revenge on his brother J'onn at last. Now, he has revealed exactly why he released Malefic and what purpose it has served. Seeing as "Crisis" is mere days away, J'onn will likely find himself involved whether he wants to be or not.
Martian Manhunter will return in "Crisis on Infinite Earths," which begins Sunday, Dec. 8 at 8 p.m. ET/PT on Supergirl, then continues in Batwoman on Monday, Dec. 9 at 8 p.m. ET/PT and 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.