He first appears as a grubby, sludge-infested spirit, referred to by Yubaba and her subordinates as a "Stink Spirit", but is soon revealed to be an extremely wealthy and powerful spirit in the Spirit Realm.
By his appearance, he is an extremely old river spirit, evident by the countless wrinkles on his face, white-colored eyebrows and the thinning amounts of facial hair and lack of teeth, the River Spirit is revealed to have a water-based body in his original form with multiple, wiry, avian legs.
In his first introduction in the film, the River Spirit is shown to be a disgusting, grimy, muck-infested spirit mistaken to be a "stink spirit" by many. However, Yubaba notes that he didn't seem like a stink spirit and ordered Chihiro Ogino to wash him in the Big Tub. After being relieved of all the human-made trash that had clogged up his body, the Unnamed River Spirit was freed from all the gunk he was carrying and revealed himself to be a grand, dragon-like spirit.
Not much of the River Spirit's personality is made apparent in the film. It is known that he is a very rich and powerful spirit with much influence in the Spirit Realm. He is shown to be very energetic once freed of his polluted burden and displays a hefty amount of gratitude to Chihiro, who freed him, by giving her a famous type of medicine as thanks. He is also generous, leaving a great amount of gold pieces on the ground as a tip to the Bathhouse workers for their service to him.
The River Spirit is assumed to be the spirit of a very large and powerful river in the Human World. Due to humans consistently dumping trash and filth into his river, the River Spirit was transformed into a filthy muddy creature called a Stink Spirit that leaves a trail of sludge wherever he walks. In hopes to save himself from the pain of being grounded by human waste, the River Spirit visits the Bathhouse where Chihiro helps him take a bath. After pulling a bicycle (among countless other man-made artifacts) from his body, the River Spirit shows gratitude by giving Chihiro a famous, emetic herbs medicine and leaves the bathhouse happily in his original form, leaving a generous amount of gold as tips for the workers.
He is not seen again in the film after this.
- "Well done."
- The River Spirit is a character that alludes strongly to Spirited Away's theme of human corruption on their surrounding environments, as seen when Chihiro pulls a truckload of man-made waste and debris from his body.
- According to Yubaba, the River Spirit is rich and powerful.
- The River Spirit is similar to Hedorah from the Godzilla series, as they both have a similar appearance and represent pollution.
- His name is never revealed in the film. Beside that, Haku is also a river spirit.