Darrell is a robot created by Lord Boxman. Darrells play the role of Lord Boxman's loyal henchmen. They are built with brains which sit inside a compartment above the head, acting as the cranium. If Darrells are ever destroyed and come back, the next Darrell will remember what happened in its previous body. He first appeared in the "Lakewood Plaza Turbo" pilot as the main antagonist and is a recurring antagonist in OK K.O.! Let's Be Heroes, in which he was first briefly seen in "Let's Be Heroes." He is also a boss in OK K.O.! Lakewood Plaza Turbo and an enemy in OK K.O.! Let's Play Heroes.
Darrell is a red robot with a slender and tall body. He only has one eye, instead of two eyes. His head is shaped like a square and holds a brain inside a light green compartment that is connected to the top of his head. He has a yellow circle on his chest that he can use to reset his robot form into a new one, along with two on the back of his hands, and also wears grayish, black robotic boots. He has very sharp fingers and sharp teeth.
Darrells are known for their trickery, persistence, and childlike behavior. He hates the heroes of Lakewood Plaza Turbo, especially K.O., Rad, and Enid. Despite his temper and evil ways, he shows a soft side via a need for affection from his father, Lord Boxman. As a result, he is very receptive to any praise that Lord Boxman might give him. Darrell also has a never-ending rivalry with his sister figure Shannon.
Darrells can be described as being rather emotionally unstable, as they are easily aggravated. They can also become easily flustered by the pettiest of insults; this is one of Darrell's weaknesses.
Darrells can be customized in various ways (though not to the extent that Shannon's can), such having a laser cannon on one arm and a giant fist on the other. Darrells can also send out seemingly endless multiples of themselves.
Another notable customization is the Big Darrell robot, piloted by a normal sized Darrell within the head compartment, which has a power level of -100. This robot can only be beaten by a hero or force that equals up to power level 100 or higher. The Big Darrell was first seen in the episode "You're Level 100!," when Lord Boxman created a robot to test KO's claim of him being level 100.
- "Lakewood Plaza Turbo" (debut)
- "Let's Be Heroes"
- "Let's Be Friends"
- "You're Level 100!"
- 'I Am Dendy" (cameo)
- "Sibling Rivalry"
- "Legends of Mr. Gar"
- "We're Captured"
- "Stop Attacking the Plaza"
- "We've Got Fleas" (mentioned)
- "A Hero's Fate"
- "KO's Video Channel" (pow card)
- "Rad Likes Robots"
- "The Power Is Yours!"
- Darrell is the first robot of Lord Boxman's design introduced to the main cast.
- Darrell secretly thinks K.O., Rad, and Enid are cool and wishes he could be as cool as them.
- In the pilot, Darrell wore a name tag. This was later removed in the shorts and the series, when "Lakewood Plaza Turbo" then became known under the name of OK K.O.!.
- In "We're Captured", Darrell asks to wear 'his costume', which is based on a sailor suit.
- Lad Boxman wears a similar suit in "Legends of Mr. Gar".