When Black Siren was rescued from Lian Yu by Helix, the agent saving her had the same clothes and boots as Sheck, likely being the same man. This lead to Sheck becoming Black Siren's contact in the organization.
Over five months later, Sheck met with Black Siren to give her the next target that she needed to kill and obtain fingerprints from in order for the group to access the International Domain Name Directory vault. He was with Cayden and Black Siren when they came across Alena and Felicity Smoak, who had broken into the abandoned Helix hideout, and escaped with them when Team Arrow interfered. Later, Sheck, Cayden, Black Siren and the rest of their group entered the IDND vault, escaping after Team Arrow once again intercepted them following a short fight. After Cayden confirmed everything was going as planned for "Arclight", Sheck boarded a private jet with him and Black Siren.
Later, Sheck was with James and Black Siren when they were joined by Anatoly Knyazev, Ricardo Diaz and Vincent Sobel, with all the members of Cayden's criminal cabal in the same place for the first time.
While waiting in one of their hideouts, members of Cayden James's criminal cabal were attacked by Green Arrow, who shot Sheck in the shoulder. Despite this, Green Arrow was surrounded and forced to retreat. Later, Sheck was along with the rest of the criminal cabal when they defeated Green Arrow and Jerry Bertinelli's forces, which lead to Jerry's death.
When the criminal cabal initiated their plan, "Arlight", taking control of Star City, Mayor Oliver Queen revealed that Cayden James was behind all the incidents and informed people of safe houses which would be unaffected by his devices. Cayden sent Sheck and Vigilante to attack one of the safe houses, but they were met with resistance from Team Arrow and the "New Team Arrow". During the fight, Sheck managed to sneak up on Wild Dog but Vigilante, revealing himself to be a double agent, fired on Sheck. Injured, Sheck fell to the ground. He called Vigilante a traitor and threatened to "take [him] to Hell with [him]" but Vigilante was too fast and fired a second shot at Sheck, killing him.
- Skilled marksman: Sheck is very skilled using guns.
- Hacking (presumed): As a member of the former hacktivist group Helix, Sheck was likely skilled in computer hacking, although it is possible he mostly served as Cayden James' personal bodyguard and enforcer.
- High pain tolerance: Sheck was able to shrug off being shot with an arrow in his arm at least twice and keep fighting. When Vigilante shot him through the shoulder, Sheck was still able to aim his gun and Vigilante required a second shot to finish him off.
- Guns: Sheck knew how to handle a pistol and was involved in gunfights.
- Sheck first appears in a flashback in "", with only his boots being seen. When he reappears in "", the first shot of his body also focuses on boots, mirroring the first episode of the season.
- While it has never been explicitly stated that Sheck is the one who rescued Black Siren, the boot shots and the fact that he was referred to as "Boots" by the producers before his name was revealed all but states this.