Niwa Daisuke
Daisuke is a typical school boy, who has a crush on a girl at his school, Risa Harada. However, because of the Niwa family heritage, his special DNA merged with that of the famed phantom thief, Dark, when he was rejected by Risa.
Mousy Dark
Dark is the entity passed on to each new male in the Niwa generation at the age of 14, once said male experiences love. He was dormant for 40 years due to the fact that Daisuke's grandfather, who was Dark's host before Daisuke, had no male offspring. It is not possible for females to be the Phantom Thief.
Hiwatari Satoshi
Always calm and composed, never showing much emotion. Satoshi Hiwatari is a distant, cold, and silent character, though these qualities never seem to affect how close he keeps to Daisuke Niwa. He is extremely intelligent and has a college degree. However, he attends Daisuke's Junior High School in an attempt to have a normal life. He acts as the police commander in charge of capturing Dark.
Krad
Krad is the complete opposite of Dark - with even Dark's name spelt backwards - and also Dark's worst enemy. Krad is the homicidal blond of the series who is the alter-ego of Hiwatari Satoshi.
Harada Riku
Riku Harada is the older twin sisters. Unlike her younger sister Risa, who prefers fashion and obsessing over relationships, Riku is more into athletics - lacrosse being her sport of choice - and academics and can be considered to be somewhat of a tomboy.
Harada Risa
The younger of the twin Harada sisters, Risa is initially the object of Daisuke's affection. However, she doesn't show the same feelings towards Daisuke as he does for her considering the fact that she feels that he is too normal and only thinks of him as a best friend since he's very kind and nice to her and she can rely on him for anything. She is a rather naive young girl.