Yoshitoki Ōima is a Japanese manga artist and writer born on March 15, 1989, in Ōgaki, Gifu Prefecture, Japan. She is the third daughter in her family, with an older sister and an older brother. Her mother worked as a sign language interpreter, a factor that would later directly influence the creation of her most famous work. As a child, Ōima was inspired to draw by her brother's collection of manga, particularly Yuzo Takada's series 3x3 Eyes, as well as the video game Chrono Trigger. She began creating her own manga while in high school.

Ōima made her professional debut by adapting Tow Ubukata's cyberpunk novel Mardock Scramble into a manga series, which was serialized in Bessatsu Shōnen Magazine from 2009 to 2012. Prior to this, while still in high school, she had created a one-shot manga titled A Silent Voice, which won the 2008 Kodansha Shonen Magazine Newcomer Award. However, due to its sensitive subject matter involving bullying and a deaf protagonist, the work faced internal resistance and was not published at that time. After gaining experience with Mardock Scramble, Ōima revisited the story, and a reworked version of the A Silent Voice one-shot was published in Weekly Shōnen Magazine in February 2011, where it received an explosive response from readers. The series was serialized from 2013 to 2014, becoming a critical and commercial success.

A Silent Voice follows Shoya Ishida, a former bully who seeks redemption by reconnecting with Shoko Nishimiya, a deaf girl he tormented in elementary school. Ōima has clarified that the story is not primarily about bullying or hearing impairment, but rather about perspective and the difficulty of understanding the person who causes harm. She drew from her own life experiences, including witnessing bullying during her school years and her mother's work as a sign language interpreter, to inform the characters and their relationships. The series received widespread acclaim, winning the New Creator Prize at the 2015 Tezuka Osamu Cultural Prize and receiving nominations for the Eisner Award and the Manga Taishō. The story was adapted into a feature-length anime film by Kyoto Animation, released in 2016.

In 2016, Ōima launched her third major series, To Your Eternity, serialized in Weekly Shōnen Magazine. The series centers on an immortal, shape-shifting being sent to Earth, who experiences life and human emotion by taking the forms of those it encounters. Like A Silent Voice, the series explores themes of connection, communication, and the outsider's perspective, though within a fantasy setting. It has also been adapted into an anime series.

Throughout her career, Ōima's work has been consistently recognized for its emotional depth and its focus on difficult forms of human connection. A recurring theme in her storytelling is the gap in communication between people, not only across disabilities but among all individuals. She has spoken about the importance of depicting silence in her work, using careful visual rules and trusting the reader to understand meaning in quiet moments. She has also expressed a personal need to include a sense of hope or redemption in her stories, noting that while real life does not always offer such resolution, her art does.

Her creative approach is informed by a sense of personal necessity, as she has explained in interviews about the origins of A Silent Voice and her decision to continue creating. She has cited the 2019 Kyoto Animation arson attack, which affected the studio that animated A Silent Voice, as a pivotal moment that deepened her consciousness of the impact her work has on readers and the importance of handling sensitive themes with care.

Beyond her major serializations, Ōima contributed an illustration for the ending sequence of the ninth episode of the Attack on Titan anime and worked on a collaboration manga titled Ore no 100-wame!! alongside other artists. Her work has earned her a significant place in the manga industry, with To Your Eternity receiving nominations for the Manga Taishō in 2018 and A Silent Voice winning awards at France's Japan Expo.