Aku

Aku is one of the central characters in the anime Demon Lord, Retry! (also known as Maou-sama, Retry!), serving as the female protagonist and the first companion the Demon Lord Hakuto Kunai meets in the game world.

She's a 13-year-old girl with short blonde hair, an androgynous appearance, and striking heterochromia (one red eye and one green eye, with her long fringe often covering the green one). When first encountered, she has an injured/infected leg that makes walking difficult, and she's in a pitiful state due to severe mistreatment.

In the story, Aku was orphaned young by disease and faced constant abuse and bullying in her village because of her unusual eyes and lowly status—she was forced to handle dirty tasks like waste disposal and was even selected as a sacrificial offering to a demon. Kunai saves her at a critical moment, after which she becomes deeply attached to him, viewing him almost like a father figure (though her feelings run stronger and include admiration/respect, with some hints of more).

Her personality comes across as pure-hearted, innocent, fragile from her traumatic past, loyal, and a bit naive or "clueless" at times—she tends to openly call Kunai "Demon Lord" in public despite his efforts to keep a low profile, which often draws unwanted attention.

Overall, she's portrayed as a sweet, endearing girl who brings a softer, more wholesome dynamic to the Demon Lord's adventures.