Shinmai Maou no Keiyakusha

Baka description:

“Hey, you said you wanted a sister, right?” First year highschool student, Toujo Basara, was suddenly asked by his father and fell into a state of panic. On top of that, the eccentric father told him he will be getting remarried. He then departed overseas after bringing Basara two beautiful step-sisters. But Mio and Maria’s true forms are actually the newbie Demon Lord and a succubus!? Basara was almost entered into a master and servant contract with Mio, but a “reversed” contract was formed by mistake, and Basara is now the master!?

Have fun!

Japanese raws:

chapter 11 here new
chapter 10 here new
chapter 9 here
chapter 8 here
chapter 7 here
chapter 6 here
chapter 5 here
chapter 4 here
chapter 3 here
chapter 2 here
chapter 1 here

Other names:

По велению адской сестры
신 여동생 마왕의 계약자
Shinmai Maou no Keiyakusha (Testament)
Shinmai Maou no Testament
The Testament of Sister New Devil