Don't be a Jerk!

After his father remarried, Kawazu Yakumaru, a high school boy who hates snakes, moved in with his beautiful stepmother Uroko, and his cute younger sister,Mana. However, he soon found out that they are actually snake women! To hide her true identity, they decided to send Mana to the same school as Yakumaru. A non-stop youthful love comedy about youkai!

(Source: Beaglee, translated)