I am Behemoth of the S Rank Monster But I am Mistaken as a Cat and I Live As a Pet of Elf Girl Vol. 1
In this new series, a knight finds himself reincarnated as a behemoth, one of the most powerful monsters in the world, and when he meets a beautiful elf girl, he's ready to fight at her side. Problem is, a baby behemoth looks an awful lot like...a housecat?!