Riri Sagara is a Japanese manga artist best known as the illustrator of the survival comedy series Are You Lost?, which is known in Japanese as Sounan desu ka?. In this capacity, she was responsible for the artwork of the manga, while the story was written by Kentarō Okamoto. The series began serialization in Kodansha's Weekly Young Magazine in January 2017 and concluded in March 2022, spanning a total of ten tankōbon volumes and 128 chapters. The manga achieved commercial success, selling over one million copies including digital editions.

Sagara's work on Are You Lost? led to its adaptation into a twelve-episode anime television series. The anime, produced by the studio Ezo'la, aired in Japan from July to September 2019. Her role as the original character designer and illustrator for the manga is the foundation of this adaptation. The series follows four high school girls who are stranded on a desert island after a plane crash and must use survival skills to endure their situation.

Beyond her primary work on Are You Lost?, Riri Sagara has also been credited as the artist for the manga Sonna Hiroki mo Isekai e. Additionally, she contributed illustration work as an end card artist for other anime series, including an episode of Ascendance of a Bookworm Season 2 in 2020 and an episode of Tawawa on Monday 2 in 2021. These contributions indicate her continued activity as an illustrator within the anime industry following the conclusion of her major serialized work.