Emi Yusa is a central character in the anime series 'Hataraku Maou-sama!' also known as 'The Devil is a Part-Timer!'. She is the human form of the hero Emilia Justina, who hails from the alternate world of Ente Isla. Tasked with defeating the Demon King, she follows him to modern-day Tokyo after he escapes there. In the human world, Emi takes on the identity of Emi Yusa and works as a call center agent. Despite her initial hostility towards the Demon King, circumstances lead to an uneasy alliance as they adapt to their new lives.