Rouge

Rouge falls from the sky like an angel and lands right atop Yusuke; however, she is plagued with a case of amnesia. All she can recall is her name. Yusuke offers her a safe place while she attempts to regain her lost memories. In the meantime, she develops feelings for the high school boy. She tries her best to repay him by cooking him meals, doing chores, and helping him with the shopping.

At one point she is kidnapped by a demon-like woman named Vega. Yusuke and Rouge’s two sisters, Kaiga & Meiga, go off to try and rescue her. They meet up with Vega who transports the three to the Underworld. There, Rouge is encased in a magical ball as her friends attempt to save her. It is revealed at this point that Rouge is the Princess of the Underworld. In the end, Vega tries to kill Yusuke. Rouge’s feelings well up inside her and she unleashes a hidden power to save him. This shows that she does have some sort of the connection with Kaiga & Meiga, and sheds some truth to the Princess of the Underworld theory.

The four proceed to live together until the day she can regain her past---her bond with Yusuke only growing.