Daisuke was just an average 14 year old boy with a crush an an average girl named Risa, or so he thought.

On his birthday he discovers he comes from a bloodline where the males turn into the Phantom Theif Dark-Mousy. It's all connected to love. When he thinks about the one he loves, Risa, a gene in his DNA reacts and he becomes Dark. He can only change back when Dark thinks about the one he loves, Riku.

Daisuke is very good at picking locks and avoiding obstacles because he had been trained to be a phantom theif since he was very young.

Daisuke is a kind hearted young boy. He is sweet and will rush to anyone's aid if need be. Daisuke's heart, however, is a place of confusion. As Daisuke evolves through the series, his love for certain characters grows. And Daisuke not only learns about the people around him, he learns about himself and grows into a stronger character.

The legendary phantom thief Dark is a creature who has lived for centuries. Within every male in the Niwa family, Dark can come alive. And in Daisuke's case, change a person.

Every time Daisuke thinks of the girl he loves, he transforms into Dark. Unlike Daisuke, Dark is moody and a little evil. Dark lives to steal artwork and it appears that no one can stop him.

There are times when Daisuke has control of Dark's body and times where Dark has control of Daisuke's body. Dark doesn't like Daisuke's body as much as his own, but enjoys causing problems for Daisuke.

Dark seems to have feelings for Riku. His feelings of love transforms Dark back into Daisuke.

Much of Dark's past is a mystery, but there are those who know him from the past. With their interference, details of Dark's past are made clear.

Even though Dark and Daisuke aren't always thrilled with each other, Dark makes Daisuke a stronger person, and Daisuke makes Dark more aware of his actions. Together, they are able to grow and learn from each other.

It may seem as if Hiwatari is the enemy, but after a while it becomes clear that Hiwatari is one of Daisuke's dearest friends.

Hiwatari is a mysterious boy in Daisuke's school. He always seems to be watching Daisuke, and records everything into his notebook.

Hiwatari lives to capture Dark. He commands a unit of guards to complete this task. However, the task of capturing Dark is harder than one would think.

Hiwatari's past is a mystery. He met Dark once long before. Now he watches Daisuke. He knows Daisuke's identity and keeps an eye out for him. Whenever Daisuke is in danger or in trouble, Hiwatari is there.

Risa is Riku's younger twin sister. Unlike Riku, it takes Risa a long time to catch on to things. Her assumptions and lack of logic create many problems for Daisuke and the others.

Risa was Daisuke's first love. It was her that allowed Daisuke to transform into Dark for the first time. Risa rejects Daisuke for the one she loves - Dark.

Riku is a girl in Daisuke's class. She is Risa's older twin sister. Even though Risa and Riku are twins, Riku is a lot brighter than her sister.

Dark seems to have a thing for Riku. Riku allows Dark to transform back into Daisuke. Although she doesn't show them at first, Riku has feelings for Daisuke. She stays by Daisuke's side through times of trouble, and the more time she spends with him, she continuously realizes more and more about him.

Riku's personality makes her one of the strongest female characters in the series.

With is Daisuke's furry little companion. Besides being Daisuke's cute little pet, With helps out Dark. With has the ability to turn into a black-winged creature. It is this creature that acts as Dark's wings.

With also has the ability to take the shape of anything it wants. This helps Daisuke out a lot. While Daisuke is stuck being Dark, With transforms into Daisuke and carries out Daisuke's life for him.

With tries to bail Daisuke out of trouble time and time again. However, at times, With has caused a lot trouble for Daisuke. With has trouble speaking and water is his greatest weakness.

Takeshi is one of Daisuke's friends at school that can be kind of rough at times and makes Daisuke do his chores. He's one of those loud and punky characters that uses a lot of slang. Takeshi's father seems to be the police inspector who's in charge of catching Dark. Takeshi is also plays a role in this. He acts like a reporter at times and video tapes Dark's trips to the museum. When Takeshi wants Daisuke to do something for him, he often bribs Daisuke with pictures of the Haradas. How nice.

There is not a whole lot known about Krad. We do know he's Satoshi Hiwatari's other half and for reasons unknown, though related to his emotions, he turns into Krad. We also know Krad wants to kill Daisuke Niwa and any other Niwa he comes across, not to mention killing Dark.

Krad is obsessed with Satoshi, and at times it seems as if he's molesting the boy. Satoshi means everything to him. He can be crazy at times, well, most of the time. Krad is a homicidal blonde. Yay.

Emiko is Daisuke's mom. She seems to be more excited about the whole 'Phantom Thief' matter than anyone else. She makes special costumes for Dark and fauns over Daisuke. She is a very interesting and amusing character, if I say so myself. She often feels guilty for her mother's death and blames herself since her mother died shortly after Emiko was born. She always wanted to be a kaitou since she was young, but since she's female, she couldn't. So she settled for being the famous kaitou's mother.

Kosuke is Daisuke's father that has been away for a long time. When he comes back home, Daisuke doesn't even recognize him, saying, "Who the hell are you?" Kosuke is shocked at this, but understands since Daisuke hasn't seen him since he was very young. Daisuke was Dark at the time which explains his tone of voice. Heh, this is probably what Daisuke will look like when he's older.

Keiji is a major producer in a television company called Saga Entertainment. He'll do anything to get what he wants and doesn't like it when people get in his way. Not much is known about him since he's only in two volumes. Keiji gets a suspicion that Daisuke was Dark and tries to find out the truth. Will he succeed and uncover Dark's identity?

Hunabashi is Keiji's assistant and helps him gather information and pictures for the company. Not much is known about this character either, besides that he works for Keiji, but he wants to try and keep Daisuke's secret just that; a secret.