Manipulation of public opinion plays a crucial role in Light Yagami's plans in the anime "Death Note." Light uses his intelligence and the Death Note to create a god-like persona known as "Kira," who punishes criminals. By manipulating public opinion through his actions as Kira, Light seeks to gain a large following and create a world that aligns with his vision of justice. This manipulation helps him evade capture by law enforcement and further his goal of creating a utopia under his control.