Cunber is a very muscular man of towering height, similar to that of Broly's Legendary Super Saiyan form. He has long spiky black hair reaching down to his thighs with a single shorter bang hanging over his face. Unlike most Saiyans with pitch-black irises, he has red-irises and visible pupils. He also retains a Universe 7 Saiyan tail which he lets sway freely, though his tail was cut off in the manga. While restrained by Fu, he wears a white straight-jacket with Fu's mark on its chest area, which also seemingly blanks out his eyes.
Once he frees himself from his restraints, his outfit is shown to be a red sleeveless shirt with blue baggy pants and white boots. Though he continues to wear a piece of the straight-jacket that covers his mouth, a piece from the left side is shown missing, which reveals a small scar from the left side of his jawline. His attire also appears to be made of similar material to Saiyan armor, as it can stretch and retain its integrity even at Great Ape size.
Not much is known about Cunber's personality. He is shown to have a rather violent and savage behavior when in battle, befitting of him being called the "Evil Saiyan" by Fu. Like most Saiyans he loves to fight. He also admits to have some respect for Goku and Vegeta right before demanding that they fight him, as well as claiming that destroying Super Saiyan Blue Vegito brought him joy.
Cunber is an ancient Saiyan. He is taken from his time by Fu and placed on the Prison Planet, he is restrained by Fu using a straight jacket and is given a Special Dragon Ball.
Cunber appears to have some history with the Super Saiyan God, as upon seeing Super Saiyan God Goku he angrily shouts over and over at the presence of a red-haired Saiyan.
Super Dragon Ball Heroes
In the game, Cunber is summoned by the Dragon Balls after Fu makes a wish with them. Evil Saiyan Kanba faces Goku, Vegeta, and Future Mai
In the anime, Cunber breaks free from his shackles inside a tower surrounded by lava somewhere on the Prison Planet. After breaking free he immediately makes a bee line towards Goku and Vegeta and upon spotting the Saiyan pair attacks them straight away. When Goku attempts to hit him, Cunber's evil ki corrupts Goku's mind and causes him to enter a berserk state where he then turns on Vegeta. Soon after Future Trunks and Coolerarrive to back up the two and after Cooler transforms into Golden Cooler he knocks out Goku and throws a Golden Supernova at Cunber though it does no harm to him. Cunber then powers up further and his restraints fall off as he asks them to fight him. Cunber strangles a struggling Trunks, preparing to obliterate him with a Désastre Eraser before Vegito Blue charges into the blast and disperses it.
"I'm amazed to find so worthy an opponent. Destroying someone like you gives me joy!"
— Cunber to Vegito before charging his Désastre Claw in "The Mightiest Radiance! Vegetto Blue Kaio-ken Explodes!"
At first Cunber and Vegito appear to be evenly matched, with an excited Fu admiring their brawl from his monitor room. After complimenting Vegito Blue's strength, Cunber uses a Désastre Claw to attack him, missing the first two hits but eventually slamming Vegito into a rock wall. The battle continues with Vegito unleashing Kaio-ken to gain an advantage, heating up to the point where their clash begins to crack at one of the chains holding the
Cunber begins to charge a giant Désastre Eraser, which prompts Vegito Blue to respond with a Final Kamehameha in return. Though Cunber's blast at first gains the upper hand, Vegito pours more energy into his attack and disperses the Désastre Eraser, the energy actually snapping a portion of one of the Prison Planet's chains. After forcing Vegito back with another Désastre Claw, the evil Saiyan launches a Power Ball into the air and
He fires another Désastre Eraser that forces Vegito to defuse, leaving a battered Vegeta wondering if he and Goku completely used up their power. Cunber continues to rampage, snapping another chain link and cracking through the sky barrier - which goes unnoticed by Fu, who is completely awestruck by the Saiyans' fight and happily demands them to keep battling.
A defused Goku and Vegeta are forced to take on Cunber, who has only suffered the destruction of a segment of his mask. He continues his rampage, swatting away Super Saiyan Vegeta and Trunks effortlessly, tanking several of Golden Cooler's blasts and knocking him into the planet's barrier causing several cracks to spread, and nearly crushing Super Saiyan Goku, who is forced to use Super Saiyan Blue and subsequently Super Saiyan Blue Kaio-ken to evade Cunber's attacks. After firing another Désastre Eraser which breaks through the barrier, Cunber is forced to cease his battle with Goku due to the arrival of Fu, who, after swiftly transforming into his Super Fu state, absorbs Cunber's Power Ball and effortlessly slashes him to the ground, knocking him out of his Golden Great Ape form.
Fu goes back to his base form and leaves, so Cunber further increases his own power, becoming incredibly enraged at the sight of Goku using the Super Saiyan God transformation. He battles Goku and soon overwhelms him.