Soichiro Yagami, Chief of Japan's National Police Agency, leads the initial Kira investigation task force. Guided by a strong moral compass and a personal motto prioritizing justice above family, he deeply loves his wife Sachiko, daughter Sayu, and son Light. He wears rectangular spectacles and formal attire, his neatly combed black hair prematurely graying under the investigation's strain. When the mafia kidnaps Sayu, demanding the Death Note as ransom, Soichiro wrestles with duty against paternal love, explicitly declaring he acts solely as Sayu's parent during the exchange. Saving her life leaves him overwhelmed by guilt and suicidal thoughts. During the mission to retrieve the notebook from the mafia, Soichiro makes the Shinigami Eye Deal with Ryuk, sacrificing half his lifespan to see names and lifespans. He identifies kidnapper Mihael Keehl (Mello) but hesitates to kill him despite justification. Soichiro suffers fatal gunshot wounds in the operation. On his deathbed, Light tries to persuade him to write Mello's name. Soichiro refuses and dies without doing so. His Shinigami eyes reveal Light's natural lifespan, convincing Soichiro of his son's innocence and allowing him to die secure in the belief Light wasn't Kira, unaware Light had temporarily relinquished Death Note ownership. Adaptations maintain this core while varying elements. In films, he confronts Light after exposure as Kira, rejecting any justification for killing, and later tells his family Light was killed by Kira to preserve their memory. In the musical, he challenges L's unethical methods in songs like "There Are Lines" and voices suspicion of Light in "Honor Bound." The television drama depicts an altered past where his absence during Sachiko's hospital death fuels Light's resentment, indirectly influencing Light's turn to the Death Note.