|Abilities:||Super Strength, Enhanced Durability|
|Voice:||Richard McGonagle (On Ben in Ben 10)Michael Reisz (On Kevin in "Kevin 11")Charlie Schlatter (On Kevin in "Framed")|
Four Arms is a Tetramand (a play on the Latin "tetra", meaning "four", and "mand", meaning "arms") from Khoros. He is the sixth Omnitrix alien to appear on the series. He first appeared in Washington B.C. when Ben needed to fight the giant mammoth that Dr. Animo reanimated.
Four Arms stands at approximately twelve feet in height, has very well developed muscles, two pairs of four-fingered arms, and the Omnitrix symbol on the upper-left shoulder during the original series. His skin is bright red and very tough, as though it is armored. A black stripe goes from the bridge of his nose to his neck (and possibly down his back). A second black strip goes from his chin to his lower lip, and he has four eyes: a main pair, and a smaller pair below them.Four Arms in the original 
Four Arms's debut in the Original Series.
Four Arms possesses tremendous superhuman strength, nearly limitless endurance, and thick skin. His strength is such that he can create strong short-to-long range shockwaves simply by smashing the ground or clapping all four hands together, dubbed the "Big Smack". Four Arms' muscular legs also allow him to leap several city blocks at a time. As shown in Ultimate Alien, Four Arms is strong enough to hold a car on each of his lower hands.
Sometimes Four Arms' bulk is a disadvantage, since the Tetramand species sacrifices speed for strength and cannot run for long distances or at great speeds. Four Arms' size also makes him unable to hide anywhere or sneak up behind anyone.
Gwen used Four Arms when she and Ben snuck into a bowling alley, throwing strike after stike, though due to the increase in her strength the bowling balls that Gwen threw crashed through the pins and into the back wall. She beat Ben in a land slide victory.Gwen as Four ArmsAdded by Linkdarkside
Four Arms reappeared in the Ben 10: Ultimate Alien episode, Video Games, shown sandwiching Ssserpent between two cars. He has grown noticeably taller, seen when compared to his 10-year-old self's version in The Forge of Creation. He sports a ponytail and his face is also more narrow, resembling that of Manny Armstrong. The recalibrate form also provides more authentic clothes of the species, appearing more like a gladiator. He is shirtless, replaced by two gold sashes that cross over his torso with the Ultimatrix symbol on his torso's center, his pants replaced by black briefs and a gold belt, and now wears gold braces on his wrists and ankles instead of gloves.
He appeared again in Escape From Aggregor, where Ben used him to fight against the Yeti which was controlled by Dr. Animo. He also appeared in the episode Hero Time, facing Captain Nemesis in a game of Tug of War and won. He next appeared in The Forge of Creation as an accidental transformation (Ben having intended to become Big Chill), helping his ten-year-old self push down a panel from the crashed Rustbucket.
In Ben 10 Franklin, he appeared as Ben Franklin's first transformation, he has his original look, but with glasses, brown hair, a pirate hat, no sleeves on his upper arms, and his skin being purple.
His Ben 10,000 form has a better developed forehead, more muscle mass, no sleeves, and a pair of jutting incisors. He has thicker skin. The Omnitrix symbol has moved to his chest. Four Arms still has his fingerless gloves and pants. He also has three curved spikes on each arm and small spikes on his shoulders