Demelza Robins was a witch and a student in Gryffindor House at Hogwarts School of Witchcraft and Wizardry. She is best known for her role as a Chaser on the Gryffindor Quidditch team during Harry Potter's sixth year, serving under his captaincy. Though a minor character, she was noted for her skill in the sport.
Demelza's early life is unknown. She attended Hogwarts during the Second Wizarding War. In the autumn of 1996, during her time at Hogwarts, Demelza tried out for the Gryffindor Quidditch team. The tryouts were led by the new Captain, Harry Potter. Demelza demonstrated considerable talent as a Chaser, particularly her skill at dodging Bludgers, which impressed Harry. She was successfully chosen for the team, alongside Katie Bell and Ginny Weasley. She played in Gryffindor's first match of the season against Slytherin. During the post-match celebration in the Gryffindor common room, a highly emotional Ron Weasley accidentally punched her in the mouth while wildly gesticulating. When Katie Bell was hospitalised after touching a cursed necklace, Dean Thomas served as her temporary replacement. Demelza continued to play as one of the three Chasers alongside Ginny Weasley and Dean Thomas for the match against Hufflepuff. Her performance in the final match of the season, which secured the Quidditch Cup for Gryffindor, is not detailed.
Demelza's physical appearance is not described in the novels. Her personality is not deeply explored, but she demonstrated the courage and determination characteristic of a Gryffindor by trying out for and succeeding on the Quidditch team. She appeared to be good-natured, as she did not seem to hold a grudge against Ron Weasley for accidentally punching her.
In the film adaptation of Harry Potter and the Half-Blood Prince, an unnamed Gryffindor girl who participates in the Quidditch tryouts is widely identified as Demelza Robins. She was portrayed by actress Katija Pevec (film).