A mysterious boy and a river spirit in the form of a dragon. He is the first to help Guest. Although he is Yubaba's apprentice, he is bound to her because he has lost his true name. He is calm, kind, and wields powerful magic. His real name is "Nigihayami Kohaku Nushi." When the Kohaku River was filled in for an apartment complex, he had nowhere to go and became Yubaba's apprentice to gain magical power. In the past, when he was still a river spirit, he once saved a young Guest.

A young worker at the bathhouse with a loud and boisterous personality. Her true identity is a white fox spirit. Among the staff, she looks the most human, similar to Haku. She is in charge of meals for Kamaji and his soot sprite assistants, and she acts as a major helper for Guest. At first, she is horrified to see the human Guest, but Kamaji smooths things over by tricking her into believing Guest is his granddaughter.

An elderly spirit who works in the boiler room of the bathhouse run by Yubaba. He has six arms and two legs, totaling eight limbs like a spider, suggesting he belongs to a spider-like race. His arms are extremely long and flexible, moving freely. He heats the bathwater by tending the boiler and prepares various herbal infusions by grinding and mixing ingredients according to the orders sent down on wooden tags. He works efficiently, using his six arms tirelessly to fetch and grind herbs, adjust valves, and take occasional sips of water.

The proprietor of the 'Aburaya' bathhouse used by the gods, appearing as a short, elderly woman. As a witch, she can use various forms of magic. She rules over others by stealing their names, which causes the victim to lose all memory of their original identity. She is eccentric and sinister, yet she possesses deep maternal love for her son, Boh.

Though he looks like a newborn infant with his hairless head and chubby body, he is much taller than Yubaba and possesses strength that even she struggles to handle. He is quite articulate, suggesting a mental age of about 4 or 5 years. He wears only a red harakake (bib) with his name written on it.

A mute spirit. He shows a particular obsession with Guest.

Kamaji's assistants. Their staple food is star candy (konpeito).

Yubaba's twin sister. Unlike the cruel and greedy Yubaba, she is kind and warm. She lives in the distant countryside and never appears at the bathhouse.