Doug is a main character who attends the University of Tokyo while also working at a local restaurant. He lives with his girlfriend, Karen, who becomes entangled with the grudge curse after beginning work at a house that is the source of the supernatural phenomenon.

In terms of personality, Doug is portrayed as a loyal and caring individual who balances his university studies with part-time work to support himself and his relationship. He demonstrates patience, affection, and a strong protective instinct toward Karen. However, he also has a skeptical and dismissive side. When Karen attempts to warn him about the presence she believes is pursuing her, Doug brushes off her fear as mere stress, failing to recognize the genuine supernatural danger she faces. This initial disbelief causes him to underestimate the threat significantly. Despite his skepticism, his concern for Karen ultimately overrides his judgment, leading him to act on his devotion even when it borders on recklessness. His mix of loyalty and doubt represents an ordinary person confronted with something beyond his understanding until it becomes too late.

Doug is motivated primarily by his relationship with Karen and his desire to protect her. When Karen leaves her research on the Saeki family murders at their home, Doug becomes worried and decides to enter the haunted house himself to search for her. His actions are driven by concern rather than any understanding of the curse itself, showing that his devotion to Karen is his central driving force.

Within the story, Doug serves as Karen's primary support system before his encounter with the curse. He visits her in the hospital after she is found in shock at the house where she worked, informing her that her elderly client, Emma, had passed away. Later, Doug is surprised when Karen appears at his restaurant to tell him about the entity following her. After Doug enters the house looking for Karen, she rushes there after hearing his message and experiences a vision revealing the history of the house. When the vision fades, Doug approaches Karen but is clearly being suffocated by the curse. As Karen attempts to lead him out of the house, Kayako's ghost appears and kills him.

Doug's primary relationship is with Karen, his girlfriend. He also has connections to other characters through the aftermath of his death. Karen's mother later tells Karen's sister, Aubrey, that Doug died in a fire that Karen supposedly caused. Another character, Vanessa, mentions to others that the house is where the girl started the fire that killed her boyfriend, referring to Doug's death. His corpse is burned when Karen sets fire to the house in an attempt to destroy the curse, and Karen mourns him at the hospital, still calling for him even as she is rescued from the inferno.

Doug shows some development in that he transitions from a skeptical individual who dismisses Karen's fears to someone who takes action, though the action he takes is entering the haunted house rather than believing her warnings. His bravery and devotion become evident in his final actions, but his inability to comprehend the supernatural threat until it is too late leads to his death. He does not survive long enough to experience significant character growth beyond this final act of loyalty.

Regarding notable abilities, Doug possesses no supernatural powers or special skills. He is presented as an ordinary young man, a university student and restaurant worker whose only notable traits are his loyalty and his willingness to act on his concern for his girlfriend, even when it places him in dangerous circumstances.