Deathstroke (real name Slade Wilson) is a member of the Light. Originally the group's enforcer because of Sportsmaster's departure, he has since risen through the ranks and became the leader of the League of Shadows.
Much like his predecessor Sportsmaster, Deathstroke is cool and efficient in the discharge of his duties. This emotionless mask does tend to slip when he is truly challenged, and a degree of impatience slips through. This is evident when he was engaging with Sportsmaster, while Tigress bantered with Cheshire. He also takes great delight in the thrill of battle, and takes a sadistic relish in taunting his opponents.
Unlike Sportsmaster, Deathstroke is far more ambitious, as he made plans to "take a seat at the table" at the head of the Light.
Deathstroke is a tall, slender man, with long white hair, and a full beard. He is missing his right eye, and wears an eyepatch, while the remaining eye is blue. His armor is primarily black and gray, with goldenrod greaves and gauntlets. He wears a matching goldenrod mask with a black area that obscures the right half of his face, including his missing eye. He wears a utility belt with pouches, and sheaths for a sword and staff on his back.
By 2018, Deathstroke has cut his hair much shorter. He also changed his armor considerably, with much more orange in its color scheme. The suit has goldenrod shoulder pads and matching greaves and gauntlets. His mask now is made of cloth and includes two long ribands jutting from the back, one black and one orange, matching the colors of the front side of the mask.
When Sportsmaster attempted to assassinate Black Manta, Deathstroke counteracted the attack by shooting the disc Sportsmaster threw. This prompted Sportsmaster to blow his way out of the cave, and make his escape by helicopter. Deathstroke fired several shots at the helicopter, but it escaped unharmed.
As Miss Martian and Lagoon Boy exited a Zeta-Tube in a junkyard, they were confronted by Deathstroke and Tigress. Deathstroke battled Lagoon Boy, eventually taking him down and injuring his leg. Tigress was then able to weaken Miss Martian long enough for Deathstroke to slap an inhibitor collar on her. The two then took Miss Martian aboard the Manta-Flyer.
Later, as Black Manta ordered Miss Martian to restore Kaldur's mind, Deathstroke observed in a ship a distance away from the Manta-Flyer to ensure that Miss Martian did not use her telepathic powers for any other reason.
Deathstroke continued to monitor Miss Martian's progress in restoring Kaldur's memories. He told Black Manta that progress was slow, not knowing that Kaldur was playing possum and that he and Tigress were trying to figure out how to save Miss Martian's life. Tigress informed Deathstroke she needed a break and Deathstroke excused her. Soon after Tigress left, Cheshire dropped into the room through a ventilation shaft, took down a Manta Trooper who had subbed for Tigress, and attacked Kaldur. Miss Martian intervened, but Deathstroke activated her collar to shut off her mental telepathy and alerted Manta about Cheshire's presence. He observed Miss Martian trying to protect Kaldur and then notified Tigress of the situation. As Cheshire and Miss Martian fought over a laser blaster, they took out Deathstroke's camera.
Deathstroke later boarded the Manta-Sub and caught Cheshire and Sportsmaster attempting to escape. He and Sportsmaster engaged each other, with Cheshire moving in to defend her father. Tigress intervened and took down Cheshire. As Sportsmaster and Deathstroke tussled, Sportsmaster mentioned how the Light betrayed him and could do the same to Deathstroke, but Deathstroke said that wouldn't happen if he took a seat at the Light's table. The battling duos were interrupted as Miss Martian arrived, who slammed Deathstroke and Tigress into the wall, allowing Sportsmaster and Cheshire to leave the sub. Miss Martian advanced on Deathstroke, who dropped explosive pellets on the ground that knocked Miss Martian away and released her telekinetic hold on him and Tigress. Deathstroke then charged Miss Martian, who telekinetically threw him into Tigress, allowing her to phase out of the sub.
Some time after her kidnapping in 2016, Deathstroke "rescued" Tara Markov from the Bedlam Syndicate. He began to train her, often brutally, but manipulated her such that she remained loyal to and dependent on him.
Later, he and Shiva caught up with Batman and his squad after they were intercepted trying to escape by Bane. Deathstroke initially fought Metamorpho but was frustrated by his powers, so switched focus to Katana. Oracle used the Batplane to lay down cover fire and extracted Batman's group.
Out on the streets, Deathstroke grabbed Tara from behind. He demanded to know why she had not shared all she knew about Halo and Vic Stone. She tried to claim they were both developing situations, but Slade correctly assessed that she had come to like the "heroes". He reminded her about how Brion, Helga and her parents had failed her in the past, and warned her that the "heroes" would turn on her too. He told her that he had always been honest with her, and gave her an antidote chip, just in case.
Later, Slade called into a conference of the Light, where they discussed Tara and Brion's escape from Gretchen Goode thanks to the antidote chip, Gretchen Goode's betrayal, and the consequences of the Anti-Life Equation.
Later still, he received a call from Tara. After Helga's betrayal and the arguments among the heroes, she had come to believe Slade had been right that morning, and asked for orders.
Deathstroke called in to a meeting of the Light, where they agreed on their next steps.
Later, he received intel from Tara that Gregor Markov was visiting them in America. He passed it on at another meeting of the Light. Lex Luthor believed their plot to make Markovia a puppet state was worth blowing her cover and told Deathstroke to send word.
Deathstroke met with Luthor at LexCorp headquarters, while the rest of the Light called in. They confirmed a final agreement on their plan, and Deathstroke ordered Tara to publicly execute Beast Boy. The hope was this would give Lex the leverage to call for a public meta-human and vigilante registration act, which would take down the existing heroes and allow them to supplant the Justice League with their Infinity, Inc..
As the mission continued and Beast Boy stopped Brion from killing Baron Bedlam, Slade urged Tara to complete her mission so no one could stop her and Brion from taking their revenge on Bedlam. But before she completed the act, Tigress confronted Tara and told her they knew about her working with Deathstroke, but offered her the chance to redeem herself. Batman had been able to tell from Slade's micro-expressions that he had been lying while talking about Tara on Santa Prisca, surprising Slade, who did not know Batman could see him while unmasked. Tara chose to side with Tigress despite Deathstroke's urging, and threw her comm to the floor. Cyborg then used the comm to hack into their computers, allowing him and Black Lightning to access LexCorp records and see that Luthor was with Slade.
In the aftermath, Slade thought the mission was a failure, but Luthor was satisfied; Brion had executed Bedlam on live television and usurped the throne, all while surrounded by "heroes" in masks. Luthor thought it was ideal for his purposes.
Deathstroke called in to a meeting of the Light. Despite Lex Luthor's legal worries, they were satisfied with how things turned out, with Markovia under their control through puppet king Brion Markov, thanks to their newest member. Vandal Savage then updated them on his latest meeting with Darkseid, where they were able to find common ground after their dispute with Granny Goodness.
In the comics, Slade Wilson is known as Deathstroke the Terminator, the world's most expensive assassin. He was originally a villain of the Teen Titans, and played a large role in the Judas Contract storyline. In the early nineties, he got his own ongoing series, which painted him even more in the light of a tragic anti-villain, burdened with guilt over the harm done to those near him.
This is his third animated appearance. He was a main antagonist in the Teen Titans animated series (where, for censorship reasons, he was referred to as "Slade"), and his alternate universe analogue was President of the United States in the direct-to-video film, Justice League: Crisis on Two Earths.