Celty is a Dullahan from Ireland who came to Japan in search of her stolen head. Her motorcycle, which appears to be a horse in disguise, possesses superhuman strength but falls short of Shizuo Heiwajima's power. She perceives her surroundings through unknown sensors that are not located on her head. Despite being headless, Celty is capable of manipulating a shadow-like substance to create objects ranging from gloves to chariots at will.
Celty resides with Shinra Kishitani and works as an underground porter. She communicates via a PDA when she ventures outside and enjoys online chatting, television, and DVDs. Celty is one of the few who knows the creator of the Dollars. Although she seems to have feelings for Shinra, she is uncertain if her emotions are genuine love. Celty becomes angry when Shinra suggests that she does not require her head. She fears movie scenes involving extraterrestrial pursuits or traffic officers.
Her head is also shown to have auburn hair and green eyes the few times it is shown on screen.
Her online chat screenname is "Setton."