Beheneko: The Elf-Girl's Cat Is Secretly an S-Ranked Monster! - S01

A young knight dies tragically while fighting demons in his duty to protect humanity. Yet fate has other plans-he awakens in the depths of a dungeon, reborn as a Behemoth, an S-class monster of immense power and one of the very creatures he once vowed to destroy. At first, he appears as nothing more than a small orange kitten. Though he possesses the overpowered ability to absorb the skills of anything he eats, his escape from the dungeon leaves him severely injured. By chance, Aria, a low-ranking adventurer, discovers him, nurses him back to health, and adopts him as her pet, naming him Tama. Despite his monstrous nature, Tama clings to the knightly honor of his past life. Recognizing Aria as his master, he swears to protect her from all threats-even if it means throwing away this second chance at life.