The 14-year-old protagonist of the story 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.    Daisuke can transform into Dark (usually unwillingly) whenever he experiences feelings of love or intimacy. Daisuke is kind-hearted, the opposite of Dark and always trying to stop Dark from performing crazy stunts to no avail. Later in the series, Daisuke gradually falls in love with his old crush&#039;s older twin sister, Riku Harada. Even though he does not look or act it, Daisuke is very perceptive and athletic - capable of jumping from heights that a normal boy could never be capable of. To hone his skills, his family sets up daily life-threatening trials once he returns home from school. A specialty of this is his gift for lockpicking (or hacking, in the case of electronically activated locks) any kind of lock in succession.    Daisuke, as a Niwa, has been trained in thievery all his life. He can dodge traps, pick locks, sneak past security, and break into almost any location. However, he prefers to create art, not steal it.

Niwa Daisuke is your average teenager, until his fourteenth birthday. He tries to declare his love to the girl of his dreams, but fails. Suddenly, whenever he thinks about this girl he turns into the legendary phantom thief known as Dark Mousy. Daisuke's mother, very much aware of this, makes him turn into Dark and steal valuable works of art for a purpose unknown to Daisuke. As the story unfolds, he learns why, and about his classmate who seems to have the same ability.
 
(Source: Anime News Network)

[Agency Profile](https://junction99.com/?page_id=1134)

He joined a theater troupe when he was 4 years old, and two years later made his acting debut in the historical drama Korczak. He remained with the theater troupe until March 2006, when he moved to Junction.

Made his voice acting debut in 1996 on [Taiho Shichauzo](https://anilist.co/anime/1577/). He auditioned and got the role of [Haku](https://anilist.co/character/385/) in the 2001 film [Spirited Away](https://anilist.co/anime/199/). The same year, he voiced the eponymous main character in [PaRappa The Rapper](https://anilist.co/anime/3736/), and the following year he started voicing Sora in the Kingdom Hearts video game series, a character who he still voices to this day.

He released his debut mini-album Soleil on June 26, 2009 and his first single album, Faith, on November 25, 2009. Since May 2010, he and [Hiroshi Kamiya](https://anilist.co/staff/95118/) formed a music duo called [KAmiYU](https://anilist.co/staff/116031/). Their first mini-album "link-up" was released on August 3, 2011.

Announced his marriage with an unspecified woman on September 3, 2021.

__Non-anime voice roles:__
- Sora - *Kingdom Hearts* series (VG)
- Cyno - *Genshin Impact* (VG) 

Daisuke Niwa is an ordinary, if slightly unlucky, middle school student. On his fourteenth birthday, he comes down with a 'condition' that has plagued the men in his family for three hundred years. When he sees his crush, Risa, he transforms into his alter ego, the phantom thief Dark Mousy. Unfortunately, when Dark Mousy sees his crush, Risa's twin Riku, he transforms back into Daisuke. The only cure for this craziness is if Daisuke can get Risa to fall in love with him ... 

(Source: Tokyopop) 

Included one-shots: 
Volume 1: Namaiki no 'N' (N is for Nishiki) 
Volume 2: OumagaAGAIN (The Demon Returns) 
Volume 4: Kanno-ke wa Kanai Anzen. (Protecting The Kanno House) 
Note: Includes 5 extra chapters.