Light Yagami (夜神月, Yagami Raito) is the main protagonist of the Death Note series. After discovering the Death Note, he decides to use it to rid the world of criminals. His killings are eventually labelled by the people living in Japan as the work of "Kira."

Light is a young man, standing at above average height with light-brown hair and brown eyes. During Part I, when not wearing his school uniform, which consists of a tan suit and red tie, he dresses fairly casually, sometimes sporting a dress shirt underneath a jacket or a V-neck sweater with a collared t-shirt underneath. During Part II, if not wearing a similar style of clothes, he is seen wearing a suit.

He is considered to be quite handsome, a trait noted by Misa Amane and Kiyomi Takada, among others.

Light receiving constant praise for his achievements may have contributed to his boredom and hubris. Light is characterized as hardworking, talented, and a natural genius. Highly perceptive and good with problem-solving skills, Light is a skilled planner and good at mapping out scenarios. Furthermore, Light is very popular among his peers and adored by his family members. However, his high intelligence, academic achievements, and constant praise from adults laid the foundation for an innate hubris and arrogance that quickly escalated after he adopted the role of Kira. Light also struggled with a feeling of boredom that was quelled once he began using the notebook.

Similar to his father, Soichiro, Light has a strong sense of justice, but this quickly becomes warped after he becomes tainted by the Death Note’s power. Believing the world to be "rotten," he uses the notebook as a means by which he can enact his will to rid the world of evil people. As Kira, Light's main goal is to create a new world free of injustice, populated only with people whom he deems honest and kind, and to rule this new world as its "God." Despite knowing the criminality of murder, Light would consider his actions the ultimate "sacrifice" to make the world a better place.