Debuting in the '80s in Marv Wolfman and George Perez's landmark series The New Teen Titans, Slade Wilson, aka Deathstroke, is one of the fiercest foes to face the Titans, the Justice League, and the DC Universe. Made into a peak human killing machine, Slade's physical achievements were matched only by his military experience and ingenious tactics.
The '90s comics transitioned him into more of an anti-hero, making him something of the DC version of the Punisher after Vigilante's book had ended. The early 2000s, however, took Slade back down a path of abject villainy, leading him to take down superhero enemies old and new. Here's how Deathstroke the Terminator was able to beat both the Teen Titans and the Justice League with little or no help at all.
Teen Titans
During Geoff Johns and Mike McKone's run on Teen Titans, the team regrouped with members from the disbanded Young Justice, which had dispersed due to the tragic death of Donna Troy, with many seeing it as too dangerous to continue being superheroes. Despite this, a new generation of Titans would come together, led by veterans Cyborg and Starfire. In the team's first big mission, Impulse goes off on his own, only to be hit with a sedative that disables his movement. Before his super-speed could kick back in, the young speedster gets shot in the kneecap by Deathstroke.
Deathstroke had killed his former butler and dear friend Billy Wintergreen and had now begun a one-man crusade against the next generation of metahumans. It was revealed that these actions were not exactly Deathstroke's own, but Jericho's. Jericho, aka Joe Wilson, was Slade's son who had been killed by his father after falling under a dark influence. In reality, Jericho used his possession powers to secretly hide in his father's psyche before being killed, waiting for the right moment to fight for control of Slade's body. After Donna Troy's death, he saw no better time to strike.
Though it is Jericho in control, the physicality, training, and actual body are all Deathstroke. These skills see him easily elude Beast Boy's attacks, as well as get launch a sword forceful enough to destroy half of Cyborg's head. He almost kills Robin and is even able to kick an arrogant Kid Flash, and is only taken down once heavy-hitters Wonder Girl and Superboy show up.
Identity Crisis
Though these actions were explainable given Jericho's possession of Slade, Deathstroke himself would later return to villainy as a mercenary looking for a quick buck in the following years. In Brad Meltzer and Rags Morales' controversial Identity Crisis, Deathstroke is hired by fellow Teen Titans villain Dr. Light to take down the Justice League. Apparently planning for the exact group that came after him, Deathstroke can fight off the likes of Green Arrow, Black Canary, Hawkman, Zatanna, Elongated Man, and the Atom. He also forces Green Lantern into a stalemate by covering his ring and trying to overturn Kyle Rayner's willpower with his own.
Having caught a second wind, Green Arrow stabs in his eye-less socket, which infuriates Deathstroke into a bloodlust. Though he nearly beats Green Arrow to death, the rest of the Justice League members can use Deathstroke's emotional state against him and tackle him to the ground. This fight, among other elements of the story, was highly controversial, as many saw Deathstroke being able to take several Leaguers on one-on-one as being an immense plot contrivance beyond the character's means. It was, however, the source of the Green Arrow/Deathstroke feud, which would go on to inspire the first few seasons of the show Arrow.
More recent examples of arguably ridiculous feats on Deathstroke's part include his kidnapping of the Flash and Kid Flash in "The Lazarus Contract," as well as his brief acquisition of technology that shielded him from attacks from Superman of all people. The New 52 also had him take on the vastly more powerful Lobo in a storyline courtesy of Rob Liefeld. Though his powers only make him peak human, Deathstroke can take on powered heroes, and sometimes villains, far more often and far more successfully than even Batman.