Mato Sato is the Japanese author and original creator of the light novel series, manga, and anime franchise The Executioner and Her Way of Life. Prior to the success of this series, Sato had already written and published two other light novel series, establishing a foundation in the industry before beginning this particular project.

The Executioner and Her Way of Life began as a light novel series, with the first volume released in July 2019 by SB Creative under its GA Bunko imprint. The series concluded in March 2025 after eleven volumes. Before its publication, the debut volume won a Grand Prize at the 2018 GA Bunko Awards, an early indication of its critical reception. The story follows Menou, a young priestess and executioner tasked with secretly killing individuals summoned from Japan called Lost Ones, whose powerful abilities called Pure Concepts pose a catastrophic threat to her world. Her mission becomes complicated when she fails to kill a summoned girl named Akari, who possesses the ability to reverse her own death using the Pure Concept of Time.

Sato has cited the works of Tomihiko Morimi as an influence on his approach to engaging storytelling. He was also inspired by the anime series Darker than Black to explore a new genre, with the initial idea for The Executioner and Her Way of Life coming from his desire to write a harsh and merciless story. Although the novels draw on established conventions of isekai narratives, Sato sought to subvert the genre by incorporating his own original elements. He called his story a stylish spy action fantasy with chūnibyō and steampunk elements, describing it as a mash-up of his interests. Sato has explained that he did not want to be subjected to rapid production and chose to release his story in a light novel format rather than online, believing this better suited the style of the narrative.

A central theme Sato identified in his work is the ability to accept oneself despite flaws and incompleteness. He sought to avoid placing characters in tragic positions solely for the sake of darkness, instead characterizing them through how they overcome conflict and depicting them as incomplete individuals who change throughout the narrative. Although he had no prior experience with darker subject matter, he included such themes to facilitate character development, also incorporating extensive worldbuilding and fight sequences, two other areas where he had minimal experience.

The manga adaptation of The Executioner and Her Way of Life, written by Sato and illustrated by Ryō Mitsuya, was serialized in Square Enix's seinen manga magazine Young Gangan from June 2020 to April 2024, with its chapters collected in seven tankōbon volumes. Both the light novel and manga are licensed in North America by Yen Press. A twelve-episode anime television series adaptation by J.C.Staff aired between April and June 2022. The series achieved commercial success, with over 400,000 copies in circulation by January 2024.