Nier is the protagonist of the action role-playing game 'NieR,' developed by Cavia and published by Square Enix. In the game, Nier is a determined father (or brother, depending on the version) on a quest to find a cure for the mysterious illness known as the Black Scrawl that afflicts his daughter, Yonah. The game's narrative explores themes of sacrifice, love, and the ambiguity of morality. Throughout the series, Nier encounters various allies and challenges, which shape his journey and character development.