I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet, Vol. 2 LN by Mitsuki Yano
The greatest demon lord in all of history, Varvatos, has reigned for several millennia as an absolute ruler. Now, there's only one thing left for him to do...enjoy the life of an average commoner! When he's reincarnated as a villager in a non-descript town, everything seems to be going as he hoped but there's just one slight problem-even when he holds back, Varvatos is still too strong! Soon, rumors about him spread and he's approached by all sorts of men, women, and assailants! The quiet life he's always dreamed of seems far away indeed...