Checkmate approached the Justice Society of America, demanding that they work for them and for them to unmask themselves. When they refused, Checkmate uncovered the JSA's secret identities on their own, and then began to hunt them down with the help of the police. The JSA members were arrested, but with no evidence or conviction to charge them with, they were released. Unfortunately knowing what the government was capable of doing to get what they wanted, the JSA chose to disband.
Amanda Waller employed Cameron Mahkent, the son of the original Icicle, as a Black Pawn to begin tracking down and killing members of the Justice Society of America. First, Icicle killed Sylvester Pemberton aka the Star Spangled Kid and then Wesley Dodds the Sandman. He then killed Doctor Fate and took the Helmet of Nabu for himself. While wearing the helmet, he faced off against a combination of the Justice Society and Oliver Queen's team of heroes. Icicle returned to the Checkmate agency hoping to kill more JSA members, but Waller revealed that she only wanted him to bring the JSA out of retirement. She then pointed a gun in his direction and said, "Welcome to the Suicide Squad"... and fired the gun.Checkmate then turned their sights on the one called Watchtower, who they knew was the key to accessing many metahumans like The Blur, Green Arrow, and the rest of their team. To do this, they first kidnapped Green Arrow after a successful diversion by Agent Mercer. Bringing him onto one of their mobile bases, Waller met with Green Arrow, demanding that he accept Checkmate's invitation to join their ranks and serve his country. Green Arrow refused and managed to escape the van. Waller hounded Tess for not making sure the prisoner was secure, telling her that failure was not an option. They realized Green Arrow's team was onto them when Detective John Jones, a Martian, managed to make his way to Checkmate headquarters at "The Castle". Waller confronted him, telling him that the alien blood sample they had received a short time beforehand was proof of alien life (the blood sample had been given to Waller by Lois Lane from a scientist torturing Kryptonian's lab). She trapped John with a cage of fire and left him while she had other matters to attend to. Meanwhile, Checkmate captured Watchtower and brought her to "The Castle" after she had investigated Checkmate's connection to Icicle. Clark Kent, the one called The Blur, arrived to rescue her, thanks to interrogating the location of headquarters out of Tess, when he met with Waller. Waller demanded his and his team's loyalty, telling him that if he refused, Watchtower would die. A power outage ironically caused by Tess allowed the Blur the time to rescue Chloe and escape "The Castle". John Jones was able to break free of his prison thanks to his Martian shape-shifting abilities and he then destroyed the blood sample, before wiping the faces of Watchtower, The Blur, and Green Arrow from Waller's memory so she no longer remembered their secret identities. Frustrated by the loss of Watchtower and therefore the entire team that could help protect them from the coming alien invasion, Waller angrily went back to her office where a Red Queen chess piece awaited her. She realized an entirely new player had entered the game.
Maxwell Lord, the Black King of Checkmate, set his sights on discovering the identity of The Blur and using that information to get to the rest of the metahumans on the planet. He helped one of The Blur's enemies, Ray Sacks out of jail in order to help him find people with any information on The Blur. They collected people who had caught glimpses of The Blur and Lord used his mind reading abilities to force the images out of their minds and project them onto a monitor. Lord offered Sacks a Black Knight position in Checkmate for his services. After nearly completing the image and kidnapping Lois Lane, who held the last piece, The Blur himself showed up. He destroyed the monitor the moment it completed his image in anger after Lord tried to rip his image out of Lois' mind. Lord escaped but was found by a man who threw him into a limo where he met with the mysterious Red Queen face to face.
Checkmate recruited Stuart Campbell, a former hacker under Tess Mercer's employ, into their ranks and with his help, they successfully hacked Watchtower of all of the information on the aliens on Earth. Stuart, wanting revenge on Tess for shooting him, disobeyed Waller to not search for Tess and did so anyway. Meanwhile, Waller used the information they had taken from Watchtower to track down half of the aliens, the ones who did not have their powers. She took their leader, Faora, while intending to kill the rest. The remaining aliens were saved by The Blur while Waller tried to press Faora for information. The aliens' true leader, Zod, attacked Waller and threw her into a windshield, hoping to kill her, when The Blur arrived, hitting Zod away and saving Waller's life. Stuart returned to "The Castle" after being unable to track down Tess where he found Waller. Waller explained that the war had begun now that Zod had destroyed many of their bases and that they needed to contact the United Nations immediately on the situation. However, Zod was also at "The Castle" and had slaughtered many Checkmate operatives. Waller and Agent Campbell made a run for it but Zod unleashed a blast of heat vision, scorching the entire fortress into an inferno.
Equipment: None known.
Transportation: None known.
Weapons: None known.
- In the comics Michael Holt was a member of Checkmate as well he was mentioned in Absolute Justice though it is unknown if he is Mister Terrific in the show or a member of Checkmate.
- This is the second DC Comics agency that has appeared on the show. The first was Cadmus Labs in season one.
- Checkmate was seen for five episodes in season nine.
- This version of Checkmate, was the first appearance of Checkmate outside of the mainstream comicbooks.
- No trivia.