Soichiro Yagami

Soichiro Yagami (夜神 総一郎, Yagami Sōichirō) is Light Yagami's father, Chief of the NPA, and a police officer that initially leads the Japanese Task Force.

Character
Soichiro is a kind man with a strong sense of justice. He cares greatly for his family and the members of the Task Force. He is a serious and responsible man that gains the respect of many. He has a strong sense of duty, and even after the police stop funding the Kira investigation he continues trying to solve the case with the Task Force.

Throughout the Kira investigation he believes that his son, Light Yagmi is innocent. In order to prove it he goes as far as to kidnap Light (who had given up the Death Note and lost his memories of ever using it) and his girlfriend, Misa Amane (who had also given up her Death Note and had no memories of it), and put them in a situation in which if Light were Kira, Light would have no choice but to kill him.

When his daughter, Sayu is kidnapped by the Mafia, he becomes conflicted over whether or not he should follow their wishes and trade the Death Note for Sayu. His delimma comes from having to choose between the duty of an officer, and the duty of a parent. As a police officer and the Chief of the NPA, he believes that handing over the Death Note to the Mafia is wrong, and the Death Note in the hands of the Mafia is too great a risk. However, he ultimately decides that he will make the exchange, not as an officer, but as Sayu Yagami's father.

Plot
As work on the Kira case begins, he becomes disappointed with the lack of police cooperation in capturing Kira, eventually joining forces with L to form a special investigative team. When L begins to suspect Light of being Kira, Soichiro is unwilling to believe his son would be capable of such a thing. Though he eventually suffers a stress related heart attack, he insists on remaining helpful to the team, going as far as breaking into the Sakura TV station using a police bus.

Much later, after L is killed and replaced by Light, he is instrumental in regaining the Death Note which Mello had pressured them into relinquishing by threatening Soichiro's daughter. Using Kira's Death Note, which Misa delivers to him under Light's instruction, Soichiro trades with Ryuk for the Shinigami Eyes. Using the eyes, he is able to learn Mello's real name, though he is fatally wounded by one of Mello's gang members and their bomb. Because Light has given up his Death Note and therefore his lifespan is visible, Soichiro dies happily believing that Light isn't Kira.

Films
Soichiro's role in the films is more or less the same as it is in the manga and anime, however Death Note: The Last Name departs significantly from the manga, in that Soichiro survives. L manages to expose Light as Kira, and the latter dies in Soichiro's arms begging him to believe that he acted as Kira to put justice into effect. A year later, on Light's birthday, Sayu fetches Soichiro from the train station, and claims he told her that Light was killed by Kira. While Soichiro wears glasses throughout the manga and anime, Takeshi Kaga only wears them briefly in the first film. He also does not have a mustache.

Trivia

 * Soichiro died about 1 hour after his shinigami eye trade, so he was in fact fated to die 2 hours later.
 * Soichiro makes a cameo apperience in Full Metal Panic: Second Raid, between Light and Misa.