Asato Tsuzuki is the central character of the narrative. Born in 1900, he died and became a Shinigami at the age of 26. Despite his death at that age, he appears slightly younger, possibly due to spending eight years in a hospital before passing away. At the start of the first book, Tsuzuki is 97 years old. Within the Shokan/Summons division, he is the oldest employee besides Chief Konoe and also the lowest-paid due to his perceived lack of competence.
Tsuzuki has a fondness for sake, apple pie, cinnabon, teasing Hisoka, and sleeping. Among his fellow Shinigami, he is notorious for his laid-back attitude and insatiable appetite. His favorite color is light green, and he maintains a flower garden featuring tulips and hydrangeas.
In the second volume, "Last Waltz," we gain more insight into his relationship with his sister. By Tankoubon 5, "Storybook," he names an unnamed female character 'Luka,' after his sister. She had instilled in him a love for dancing and gardening, both of which he excels at, along with cooking, though his culinary efforts are often disastrous. This is evident in Volume 4, "Hokkaidō," where it's revealed that a muffin made by Tsuzuki caused the Queen to go missing temporarily.
Throughout the series, Tsuzuki forms a close bond with his partner, Hisoka. He shares a good friendship with Watari and occasionally strained relations with Tatsumi, who was once his partner. Tsuzuki generally gets along well with most Meifu employees, except for Hakushaku, who persistently flirts with him, and Terazuma, with whom he shares a fierce rivalry. His relationship with Muraki is turbulent; despite despising Muraki for his cruelty towards Hisoka and others, Tsuzuki's self-sacrificing nature prevents him from killing Muraki outright.
Although one of the cheeriest characters, Tsuzuki conceals a dark past. Both manga and anime hint at terrible acts he committed while alive. It's suggested that Tsuzuki may have been responsible for numerous deaths, either intentionally or as a side effect. This comes to light during his possession by Saagantanasu in the Devil's Trill Arc. Dr. Muraki reveals that Tsuzuki was a patient of his grandfather for eight years and that Tsuzuki might possess demon blood, evidenced by his purple eyes, which deeply unsettles him.
Tsuzuki commands the power of twelve Shikigami and ofuda magic. He exhibits remarkable stamina, capable of enduring significant physical damage without dying and healing almost instantly. While this ability is later shown to be common among Shinigami, Tsuzuki was the first to display it, suggesting it stems from his pre-death capabilities.
