Cell (セル)
Background
Cell has as an original personality with various other characters' personalities added in; the computer redesigned the weak parts of the original personality, adding in the personalities of various different characters to make him the perfect weapon. Throughout the Androids Arc, Cell's personality changes drastically with each transformation. At first, Cell's desire to complete his evolution by absorbing both Android 17 and Android 18 is what fuels him. Upon reaching his final form, his eagerness to test the limits of his newfound power is what defines his character.
Cell is unique among most villains of the series in that he is quite sophisticated. Because of his genetic composition from other warriors, he is able to psychologically manipulate those warriors and exploit their weaknesses to his advantage.