I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet: Season 1, Episode 1
1 - 1: The Elf Girl and the Knight's Vow
A knight dies and is reincarnated into a baby Behemoth, an S-rank monster that looks just like a cat! A novice D-rank adventurer, Aria, adopts him as her kitty cat!