Ango Sakaguchi is recognized as an original creator in the context of anime and manga not as a contemporary artist, but as the author of classic Japanese literary works that have been adapted into these visual mediums. His role is that of a source material writer, with his stories serving as the foundation for anime productions. A notable example of this is the Aoi Bungaku Series, a twelve-episode anime that adapts six major works of Japanese literature; Sakaguchi is the credited author for the segment adapting his short story In the Forest, Under Cherries in Full Bloom, which covers episodes five and six of the series.

Sakaguchi was a novelist and essayist active in the mid-20th century, born in 1906 in Niigata Prefecture. His early life was marked by a rebellious nature, and he adopted the pen name Ango after a teacher remarked that he did not live up to his given name. He later studied Indian philosophy at Toyo University, where he immersed himself in the study of Buddhism and multiple languages. His literary career began in the early 1930s, but he rose to prominence in the years immediately following World War II. He became a leading figure in the literary movement known as the Buraiha, or "Rogue School," alongside contemporaries like Osamu Dazai. This group was characterized by a critical, iconoclastic stance toward traditional Japanese values and social structures in the postwar era.

Among his most significant works is the 1946 essay Discourse on Decadence, which argued that in the aftermath of Japan's defeat, true humanity could only be recovered by stripping away false ideologies and embracing a more authentic, if morally ambiguous, state of being. This philosophy was famously illustrated in his contemporaneous novel The Idiot. Beyond such philosophical and literary fiction, Sakaguchi was also an accomplished mystery writer. His novel The Discontinuous Murder Case received the Detective Writer's Club Award in 1949.

Sakaguchi's influence extends to other anime and manga-related works beyond the Aoi Bungaku Series. His collection of detective stories, Meiji Kaika Ango Torimono-chō, served as the source material for the 2011 anime series Un-Go, which reimagines his detective character in a futuristic setting.

His artistic identity is defined by a relentless critique of cultural conformity and a deep exploration of human nature stripped of societal pretense. Recurring themes in his work include postwar social decay, the necessity of decadence as a form of rebirth, and a fascination with the darker, irrational aspects of human psychology. His significance in the industry is that of a foundational literary figure. His writings, born from a specific period of Japanese history, provide a rich, intellectually challenging source of material for anime creators seeking to explore complex themes and adapt canonical stories for a modern audience.