Slav is a brilliant alien engineer held prisoner by the Galra Empire in Beta Traz and freed by the Voltron team to assist in the defeat of Zarkon. His technology is utilized by the Blade of Marmora, and his knowledge and technology is sought after by the Galra Empire as well. He developed gravity-bending technology that could create pockets of space-time capable of concealing entire outposts.
Slav has the appearance of a fairly tall bipedal alien with four pairs of arms, a long thick tail, and yellow beak-like mouth. He has no apparent nose, but does possess a pair of triangular ears on the sides of his head. Slav averages on the shorter side of human height. The top of his head and tip of his tail are blue, while the rest of his body is gray with a white chin and hands. He has four appendages dangling from his chin, and two that sprout from the top of his head.
Slav wears a dark gray turtle-neck prison suit with light gray pockets lining its front for each pair of arms he has; Slav tends to keep at least three pairs of arms tucked away in these pockets. It has a cutout for his tail, and the bottom portion of the suit for his legs is black.
The Galra Empire once imprisoned him in a highly fortified installation known as Beta Traz, where he was subjected to torture to extract his knowledge for the Galra Empire. The Paladins of Voltron, Shiro, Lance and Pidge eventually staged a successful rescue attempt and helped him escape Beta Traz.
Slav was later called upon to build another gravity generator to conceal an enormous Teludav, intended for use against Zarkon's command ship.
While his technological prowess impresses even Hunk and Pidge, Slav's mind thinks in such scientific extremes that he has obsessive-compulsive tendencies, fearful that his actions may have detrimental effects on possible alternate realities that would lead to the demise of himself and others within those realities or the current reality that he occupies. However, this contributes to him being fearful of just about everything from him possibly drowning from a puddle to breaking an quantum reality of his mother's back if he stepped on a crack. His cowardice and antics nearly puts his rescue mission in jeopardy and even riles up the normally cool-headed Shiro. However, he does have moments of courage when he opened the hangar doors to the Beta Traz so he and the Paladins could escape.
Amongst his paranoia, Slav can be extremely critical of other's disrespectful or detrimental behavior, or their illogical design choices, such the use of zip-lines when the same designers have hover technology.. Regardless, he seems to have no malicious intent and seeks to help defend the good in the universe, being a quick thinker and not afraid to take action when the time calls for it. Unfortunately, Slav sometimes does not understand that someone is asking him to perform an action in the reality he currently occupies, and not an alternate one.
Slav is able to create highly-advanced technology like a space pocket dimension and a gravity generator to hide an enormous teludav. It's because of his genius however that the Galra imprisoned and tortured him in order to steal his technology for themselves.
Slav does not have any notable combat prowess, but his strength lies in the vast scientific knowledge in his mind and his extreme skills as a mathematician, physicist, and engineer. Slav has been able to create technology to fold space-time itself to hide entire bases of operation for the Blade of Marmora using gravity generators. Physically, he is quick on his two feet and very nimble, being difficult to catch and easily climbing to high places out of reach. With his multiple arms, he can type on a dashboard console in several places accurately without paying much attention.
- Mitch Iverson took heavy inspiration from Nikola Tesla when developing Slav's character. The other staff pushed for Slav to be more "space crazy"; Mitch did not know how to conceptualize such a character until after watching an episode of Rick and Morty.
- Blue light has a frequency between 606 to 608 terahertz, which is Slav's lucky range of terahertz.
- Another of his species was seen back in the first season, as one of the prisoners rescued during the mission to recover the Red Lion.
- In an alternate reality, Slav is shown to be a surprisingly aggressive and competent fighter, proficient in firearms as well as using his agility and tail as weapons. It's enough to make one wonder how much of his current OCD behavior might be a result of the torture he suffered at the hands of the Galra Empire, rather than an innate part of his personality.