A race of deadly robots from the planet Sark, as well as occupying the Red Sentient planet. Their entire existence is based on logic and the conquest of other worlds. They were created to be an army for the Red Sentients, but Zemerik rebelled against Krytus and took control of the Sark until Krytus was freed from the Krypt Zone. After the events of Get Zemerik, Blue Sark no longer exist. Currently, Red Sark still remain, though no longer aggressive due to the new alliance between the Red and Blue Sentients. It's possible the Red Sentients didn't create the Sark, but merely found the schematics for them because of the existence of a Factory Battle Zone older than the Sentients themselves. Additionally, the Alpha Code and the Old Sark of the Badlands point to a more ancient origin. Considering these facts, it is actually more likely that The Ancient Ones created the Sark.
- Lord Zemerik (voiced by Michael Dobson) - The leader of the Sark with an Electric Whip for combat. He also has the ability to turn Red Zurk to his command, though the Red Sentients can turn them back. Zemerik's head can also operate independently when separated from his body. He emphasizes logic and considers organic beings inferior. Originally built to lead a Red Sark Army, in The Crimson One, it is revealed that Zemerik gained free will after Vert was sent back in time and uploaded a virus, which allowed Zemerik to betray Krytus, imprison the RS5, and turn the Sark blue. Presently, he has no memory of Vert during that time (possibly due to a side effect of the virus). Zemerik and Zug were the only Sark not under Red Sentient control. In The Blue Tide, they attempted to create a Blue Sark Army resistant to conversion, but the plan failed when the BF5 shut down the Factory Battle Zone that was manufacturing them, thereby forcing Zemerik and Zug back into hiding. In Get Zemerik, he was reprogrammed by a band of Green Zurk, and underwent a radical personality change as well as a slight physical change, which involved his eyes going green and the symbol representing the Alpha Code engraved into his forehead. He then was terminated by Krytus and thrown into a pit. His final fate is undetermined with the appearance of the Old Sark of the Badlands who resurrects the former dictator.
- Zug (voiced by Brian Drummond) - Zemerik's second in command. Zug is very strong and has three drill fingers on his left hand, but is somewhat slow-witted. Aside from Zemerik, Zug is the only Sark with free will, and his primary mission is to follow and serve Zemerik, even at the cost of his own existence. Like Stanford, Zug hates the planet Vandal. He was also the first Sark turned blue after Zemerik gains free will. He was deactivated in the Toborian Badlands after being badly damaged by an ion storm and giving his power core to Zemerik, though his body was taken by the Green Zurk and dumped into the pit with his fallen master. His final fate remains to be seen.
- Zurk - Common and disposable minions for Zemerik and later Krytus, they make up most of the Sark population. There are 2 types of Zurk: The Humanoid versions that drive the Zentners and the small wheeled versions, or Mini-Zurk, which roll about on their own. Generally, Zurk are mindless and will even destroy themselves if ordered to do so. However, if a Red Sentient is nearby, Zemerik's control over the Zurk is overridden, upon which they turn red and use more aggressive tactics. They speak in a series of beeps and robotic noises, but in one of the webisodes in is revealed that they know the terms "Warning" and "Intruder alert".
- Sark Sentries - Small flying scout devices that patrol the Sark Homeworld in the first season and patrol for the Red Sentients in the second season. There are larger versions armed with blasters, used for hunting.
- Alpha Sark - Discovered in Get Zemerik, these outcast and obsolete green Zurk were banished to the Torborian Badlands by Zemerik long ago. Remarkably, not only were they able to survive there, they even gained intelligence and built a hive-city of their own. They also established a cult that worships something known only as the "Alpha-Code", which makes them immune to any attempts at conversion by Zemerik and presumably the Red Sentients. They wear cloaks wrapped around their heads like hoods and carry electro-staves. They are also able to speak, and operate individually.
- Alpha Code - A corrupt program or virus that turns Sark green, making them Alpha Sark. The affected consider this code "enlightenment". It first appears in Get Zemerik, where Zemerik (and possibly Zug as well) gets infected by it. It could be possible that it might convert Red or Blue Sentients into Green/Alpha Sentients.
- Old Sark of the Badlands - Originally thought to be no more than a myth, this ancient robot appears to be the leader of the Green/Alpha Sark. Seen at the end of Get Zemerik in the pit Zemerik and Zug were thrown into, where he resurrects Zemerik as his new servant.