Honoka

was a kunoichi working with the researchers on a remote island.

Background
While researchers worked on the Ultimate Summoning Animal, Honoka was assigned to restrain the beast using her sealing techniques. However at some point in time the beast got too powerful for her technique to restrain it and it killed everyone.

Appearance
Honoka had dark eyes and long red hair in which she wore a white band. She wore a purple, sleeveless kimono blouse with yellow trimmings held close by a traditional obi with a long, streaming bow tied to it, mesh armour underneath it and a short white skirt. She seemed to prefer going barefoot.

Adventures at Sea Arc
With her soul unable to find rest, she roamed the island as a spirit waiting for an opportunity to fulfil her duty.

Trivia

 * Given her red hair, skill in sealing techniques, and the history of the Uzumaki clan, Honoka was suspected to be a member. A book in an old abandoned house on the island even mentions finding a survivor of a certain clan of ninja.