Emi Yusa

Emi Yusa (遊佐 恵美) is a fictional character and the female protagonist of the light novel and anime series The Devil Is a Part-Timer! Born Emilia Justina (エミリア・ユスティーナ Emiria Yusutīna), she is the heroine that originally defeated the evil overlord Satan Jacob, forcing him to retreat to Japan. Choosing to follow him and ensure his destruction, Emi discovers her magical powers are severely reduced in Japan. Forced to take find employment as a call center agent, Emi eventually discovers Satan has earned an honest life and decides to keep tabs on him to ensure he doesn't fall back to his old evil habits. Later, she falls in love with him.