I've Been Killing Slimes for 300 Years and Maxed Out My Level

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, which began serialization on the user-generated novel site Shōsetsuka ni Narō in 2016. The story follows Azusa Aizawa, an office worker who dies from overwork and is reincarnated as an immortal witch in a fantasy world, where she spends three centuries defeating low-level slimes to maintain a peaceful existence until her level maxes out. The premise explores themes of work-life balance and chosen family, serving as a prominent entry in the 'slow life' subgenre of isekai fantasy.

The 2021 television anime adaptation was produced by studio REVOROOT and directed by Nobukage Kimura. The series was designed to maintain the lighthearted, episodic aesthetic of the original source material, emphasizing vibrant character designs and a cozy, low-stakes atmosphere. Upon its release, it was generally well-received for its gentle humor and the chemistry between the core cast of characters, providing a contrast to the high-stakes action typically associated with the fantasy genre at the time.