Nataku is a paopei human, a living hybrid of a human and a magical artifact known as a paopei. His origin begins before his birth: the child within his mother Inshi had already died in the womb, but the immortal Taiitsu Shinjin placed a reiju, a type of paopei that contains a soul, into her pregnant belly. Inshi then went into labor and gave birth to a giant meat egg. Nataku's father, Li Sei, intended to cut the egg apart and bury it, but Nataku burst out of it on his own, already wearing three paopei. As a child, he angered a dragon river king and, to protect his parents from being killed, willingly died to satisfy the dragon's fury. However, because his reiju was not destroyed, he could not truly die. His mother built a shrine for him and placed the reiju inside, believing him dead. His father later smashed the shrine and threw the reiju into a river, an act that caused Nataku to develop a deep and lasting hatred for his father. After that, Taiitsu Shinjin rebuilt Nataku's body out of a lotus flower, giving him a new form.

In terms of personality, Nataku is quiet and displays few emotions, with irritation being the most common one he shows. His typical reaction to situations is to threaten violence or to immediately attack. He is not particularly intelligent and rarely considers the consequences of his actions. He is stubborn and bossy, and he often rudely demands that Taiitsu repair his paopei or create new ones. Despite his cold demeanor, he cares deeply for his mother and has a noticeable soft spot for children, especially orphans; he allows the young boy Kou Tenshou to ride on his back. Nataku exists largely for combat and is more directed by the protagonist Taikoubou than acting on his own initiative. His motivations are simple: he fights because he is told to, and he holds a lasting grudge against his father, though he never actually kills him despite having many opportunities.

Nataku's role in the story is that of a powerful but straightforward fighter who supports Taikoubou in the mission to seal away the antagonists. He does not drive the plot but provides essential combat strength. His key relationships include his creator Taiitsu Shinjin, who supplies him with weapons; his father Li Sei, whom he resents; his mother Inshi, whom he loves; Taikoubou, who directs him in battle; and Kou Tenshou, a child for whom he shows unexpected kindness. Over the course of the series, Nataku receives multiple upgrades to his paopei, enhancing his capabilities, but his personality and basic role remain largely unchanged.

Nataku's notable abilities come from the various paopei he wields. His basic equipment includes Fukarin, boots with metal wheels that allow him to fly; Kenkonken, a pair of iron bracelets that act as homing missiles with tremendous impact; Kontenryou, a red cloth worn on his waist that can control water; Kinsen, a cannon mounted on his shoulder that fires beams of destructive light; Kasensou, a spear that can extend its reach; and Kyuryushinkatou II, a container that can be used for either protection or imprisonment. Later in the story, he also receives Kinkousen, a super paopei originally belonging to Chou Kou Mei that can summon dragons and is among the most destructive weapons in the series. These paopei make him a versatile and formidable combatant.