Rikka is the female protagonist of the story, a girl in the same class as Yūta who moved in with her older sister who lives above Yūta's apartment. She is an intensely delusional girl who believes herself to possess a "Wicked Eye" (Jaō Shingan, lit. True Eye of the Evil King) and as such always wears a medical eye patch and bandages around her left arm, though she has no injuries. Despite being quite attached to Yūta, she is cautious of strangers and adopts a battle pose whenever she meets someone for the first time. Her fantasy weapon of choice is a frilly parasol which she wields as a sword. For her delusional operations, she often dresses in a mostly-black gothic dress and hose. She is also rather clumsy, often tripping over and forgetting things. The origin of her delusions came from Yūta himself, without his knowledge.