S-Rank Monster no Behemoth Dakedo, Neko to Machigawarete Erufu Musume no Kishi (Pet) Toshite Kurashitemasu
I Am Behemoth of the S Rank Monster but I Am Mistaken as a Cat and I Live as a Pet of Elf Girl, I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet, I'm an S-Rank "Behemoth" Monster, but I'm Living as a Knight (Pet) of an Elf Girl, Soy un monstruo de rango S, Behemoth, pero me confundieron con un gato y ahora vivo como el caballero (mascota) de una chica elfa., Sランクモンスターの《ベヒーモス》だけど、猫と間違われてエルフ娘の騎士として暮らしてます, 虽然是S级魔兽“比蒙巨兽” 却以猫的模样、成为精灵娘的骑士的日常
Elven girl, “Aria” is an adventurer. A small beast with an adorable face embraces Aria’s fruitful chest, she decides to keep it as a pet and names it “Tama”. At first sight it’s just an average cat, but Aria has yet to notice that Tama is a former Knight and that his identity is not a cat, but a young monster of the strongest class “Behemoth”.