Orphaned early, Hikage grew up in an institution where her expressionless face drew ridicule; other children taunted her as "dead face." Unable to bear this, she fled the orphanage at eight, surviving on the streets until discovered by a gang of thugs. Their leader, Hinata, became a protective surrogate mother who embraced Hikage's emotionless nature, assuring her it was fundamental to who she was.

Hikage's world shattered when a gang war erupted. Hinata sought peace talks but was killed; Hikage later found her body discarded in a dumpster. This loss triggered Hikage's first tears and a surge of internal emotion she described as a "drip" or "rain." She kept Hinata's knife as a sacred memento, believing it held Hinata's spirit.

Presumably due to her criminal ties, Hikage was recruited into Hebijo Clandestine Girls' Academy. She rapidly ascended to the Elite Class during her first year, becoming its second member after Haruka. Serving as a shinobi for Hebijo became her primary occupation.

In the *Bon Appétit!* spin-off, Hikage is pursued by Haruka seeking to test experimental drugs on her. Recalling a prior "samba drug" incident that caused her to dance naked publicly, attracting police, Hikage enters a cooking competition to escape. During the event, she defeats opponents like Daidōji through cooking battles and wordplay, ultimately tricking Haruka into consuming her own samba drug. Winning the competition, Hikage is recruited by a street vendor impressed by her culinary skill and puns. She subsequently works festival food booths, using wordplay to draw customers. Though her expression remains unchanged, she internally acknowledges a possible suitability for this life and temporarily sets aside her shinobi duties for the festival season.