Katsumi Shibata, handsome and popular, attended elementary school with Takashi Natsume. He bullied Natsume for claiming to see supernatural beings, branding him a liar and contributing to Natsume's childhood isolation. Years later, Shibata encountered a spirit named Murasaki in a park. He developed romantic feelings for her while doubting she was human. Seeking confirmation, Shibata approached Natsume, acknowledged his past mistreatment, and expressed regret. Natsume initially dismissed Murasaki as human but later corrected himself, revealing she was a spirit. An angered Shibata called Natsume a liar again, but witnessed Murasaki's true form and disappearance. This led to his sincere apology to Natsume and their reconciliation.

During season 6, Shibata contacted Natsume to investigate a local haunted mansion. Natsume, accompanied by Kaname Tanuma and Nyanko-sensei, joined him. At the abandoned house, Natsume identified two doll-like spirits, the Nitai-sama. The spirits followed the group to Tanuma's temple, where protective talismans and Nyanko-sensei's intervention were needed to subdue them. Afterward, Shibata met Natsume again, offering sweets in thanks. During this meeting, Nyanko-sensei accidentally spoke aloud, revealing his non-feline nature and startling Shibata.

Shibata's surname combines the characters for "brush/firewood" and "field/rice paddy"; his given name means "self-denial" or "self-control." He remains one of the few humans aware of Natsume's ability to perceive spirits and maintains occasional contact. Through his interactions with Natsume and the supernatural, Shibata demonstrates personal growth from his earlier skepticism and bullying tendencies.