One of the major villains from the dragonball universe. He was created by
Dr. Gero (later dubbed android 20), and was created to incorporate all the cells of the best fighters in the universe. By weaving all their cells together from each fighter, he is able to inherit their abilities and fighting techniques. Like Frieza, he has the ability to survive anywhere, like Piccolo, he can regenerate his anatomy if his core is not damaged (in his case, one cell is enough to regenerate from), Vegeta's fighting genius, and attitude, Goku's natural aptitude for fighting, and the young but powerful Gohan.
Cell cannot reach his full potential until he absorbs
Android 17 and
Android 18. Once he does, they are permanently integrated into his design, giving him great power. Once he absorbs them, even if he loses
android 17 or 18's body, he is still able to retain his perfect power (prior to exploding) after blowing himself up, leaving one cell he can regenerate from, and giving him a
zenkai increase, making his power substantially greater, enough to kill Future Trunks with one blow, and power that rivals that of Super Saiyan 2 Gohan.
Example:
Cell holds a tournament called "The Cell Games" after he becomes complete in order to test his new power.
Cell is arguably the villain with the most potential. After he blows himself up out of fear, just after throwing up
android 18, making him revert to his semi-perfect form, he has one cell left and regenerates from that cell, making him even more powerful than before because of his saiyan dna. This form is referred to by fans as "Super
Perfect Cell". Putting his strength on par with (but not as strong as)
super saiyan 2 Gohan. Theoretically he could just keep blowing himself to smithereens over and over again until he is the strongest fighter in the universe, making him no match for even Gohan. But he instead never blows himself up again and opts to return to Earth to face Gohan again with his new power.