Kaworu Watashiya is a Japanese manga artist born on January 3, 1972, in Tokyo, Japan. The artist uses the pen name Watashiya Kaworu (私屋 カヲル), which employs the katakana character "ヲ" in place of the more common "オ," a stylistic choice stemming from a fandom for the singer-songwriter Kenji Ohtsuki. Watashiya is a female creator, a fact that is sometimes a point of clarification for readers who associate her most famous work with a male perspective.

Watashiya's career as a published manga artist began in the early 1990s. The debut work was the Shōnen Sanpakugan series, which ran from 1992 to 1993. Throughout the 1990s and early 2000s, the artist created a diverse range of manga across various demographics and genres, including works like Cotton 200%, Inu to Ojō-sama, and Oedo Musume Ninja, many of which were published by Shogakukan. This early period established a career marked by a versatility that would later become a hallmark of the artist's professional identity.

The most notable and internationally recognized work is Kodomo no Jikan (こどものじかん), a manga series that was first introduced as a two-part pilot chapter in the inaugural issue of Futabasha's Comic High! magazine on March 2, 2004. Following its positive reception, the series began full serialization on May 22, 2005, and concluded on April 22, 2013, spanning 13 collected tankōbon volumes. This work became the first of Watashiya's creations to be adapted into an anime, serving as the foundation for multiple related animated projects. The story centers on a young elementary school teacher, Daisuke Aoki, and his complex relationship with his student, Rin Kokonoe, a precocious girl whose behavior masks a traumatic past.

The success of Kodomo no Jikan led to a significant expansion of its story into other media. The initial anime adaptation was a 12-episode television series that aired from October to December 2007. This was preceded by an original video animation (OVA) titled Kodomo no Jikan: Anata ga Watashi ni Kureta Mono, released on September 12, 2007. A second anime season, Kodomo no Jikan Nigakki, was released as a series of four OVAs between January and July 2009. A final OVA, Kodomo no Jikan: Kodomo no Natsu Jikan, was released in January 2011. Additionally, Watashiya authored a light novel based on the series, which was published by Futabasha in January 2012.

Beyond Kodomo no Jikan, Watashiya has maintained an active career with a variety of other works. These include the seinen series Chibi to Boku, which ran from 2000 to 2007, the comedic Dame Yome Nikki from 2008 to 2010, and subsequent series such as Joō-sama no Eshi (Queen's Artist), which began serialization in 2014. The artist has also worked in the boys' love (BL) genre with titles like Koi ni Ochita Incubus and its related series, published in Comic Signal magazine. This body of work reflects a broad creative range, encompassing seinen, shōjo, comedy, and supernatural romance.

A consistent aspect of Watashiya's artistic identity is the focus on complex, character-driven narratives that often explore challenging or controversial themes. The work is characterized by a unique art style that combines child-like and innocent character designs with mature storytelling. Known for creating female characters who embody independence and intelligence regardless of their age, the artist's storytelling is frequently described as a blend of lighthearted school-life comedy and deeper psychological drama. This approach has resulted in work that is often categorized as seinen, a demographic aimed at adult men, which typically features complex plots and realistic themes over action-oriented narratives.

Watashiya's significance in the industry is tied to both the popularity and the contentious nature of Kodomo no Jikan. It was the first of the artist's works to be licensed for an English-language release. However, the initial license by Seven Seas Entertainment in North America was ultimately cancelled due to concerns over the controversial subject matter, which revolves around the relationship between a child and her teacher. The series was later licensed by Digital Manga, Inc., which successfully funded its English localization through a Kickstarter campaign in 2016, demonstrating a dedicated fanbase willing to support its publication despite ongoing controversy. This history highlights the cultural differences in perception regarding manga content and places the artist at the center of ongoing discussions about artistic expression and censorship in the medium.