The manipulation of information plays a crucial role in Light Yagami's plans as he uses it to manipulate public opinion and control the narrative surrounding Kira, the persona he adopts as the self-proclaimed god of the new world. By controlling the flow of information, Light is able to influence how people perceive Kira's actions and create an atmosphere of fear and worship around himself. This manipulation helps him evade suspicion and maintain his facade as a righteous and just individual while carrying out his plans to rid the world of criminals.