Slime Taoshite 300-Nen, Shiranai Uchi ni Level Max ni Natteshimatta #15

Slime Taoshite 300-Nen, Shiranai Uchi ni Level Max ni Natteshimatta, widely known as I've Been Killing Slimes for 300 Years and Maxed Out My Level, originated as a light novel series written by Kisetsu Morita and illustrated by Benio. The series began as a web novel on the user-generated publishing site Shōsetsuka ni Narō in 2016 before being picked up for print publication by SB Creative under their GA Novel imprint. The narrative follows Azusa Aizawa, an office worker who dies from overwork and is reincarnated as an immortal witch, choosing to live a peaceful life by casually defeating slimes for three centuries, inadvertently reaching the maximum level.

Issue number 15 serves as a significant installment in the ongoing light novel series, which has maintained popularity for its lighthearted fantasy tone and emphasis on the slice-of-life genre. Benio’s character designs are central to the work’s identity, employing a clean, vibrant aesthetic that complements the comedic and relaxed atmosphere of the story. The series has been well-received by fans of the isekai subgenre, eventually leading to a successful manga adaptation and an anime series that helped broaden the franchise's reach beyond its original digital and print readership.