The second season of Shinmai Maou no Testament.

After two demon girls, Maria the succubus and Mio the demoness, force Basara into a contract that makes him their master, the trio form a complicated master-servant relationship. Basara is the last descendant of a demon-fighting hero clan, but as master of two demon girls, he finds himself defending them instead of fighting them.

(Source: Funimation)