Keima's first conquest. An athletic, cheery 17 year old girl, Ayumi is a member of the school's track-and-field team and Keima's classmate. She and Keima are often paired up for cleaning duty together which the latter does not like her due to her absentmindedness of running careless into people. As Keima's first target, he tries to get her interested with him by showing his support with Elsie's help while she is training for the upcoming track-and-field tournament. While she at first is annoyed with his actions, she eventually gets use to him. However, the day before the tournament, Ayumi is confronted by jealous seniors and sprains her ankle during practice. However, Keima figures out she faked her injury because her meeting with the seniors made her question her confidence. Keima consoles her and tells her to believe in herself, which makes her fall for Keima and kisses him, which forces the spirit out and be captured by Elsie. After winning the tournament and getting praised by her seniors, she becomes more eager to spend time with him and starts calling by his last name Katsuragi instead of his nickname Otamegane.
She is also friends with Elsie, Miyako, Chihiro and Yui where they a form a rock band called the "2B Pencils" with Ayumi as the Guitarist. Recently, Keima has suspected that she maybe a Goddess host due to Ayumi being interested with him and getting jealous over Kanon's confession to Keima. During Keima's search for the Jupiter Sisters, Keima gets sick and uses it as pretense to have Ayumi visit him to to determine if she is a Goddess host.
The cause of Ayumi's negative emotions was peer pressure from her seniors and her lack of confidence.
Her surname is derived from Takanohara Station(高の原駅Takanohara-eki?) and her habit of tying up her hair during track-and-field is a homage to Dōkyūsei's heroine, Misa Tanaka.
