Jinx to-Ennien was a Sivaoan who was present when members of the Enterprise crew, including James T. Kirk, Uhura, and Chekhov, made first contact with the Sivaoans. Jinx was a 'child' by Sivaoan rules.

• For a Sivaoan to be given adult status, he or she must complete the Walk, a rite of passage. Jinx had attempted the Walk twice before meeting Kirk, and failed. Her companions on the earlier Walk attemtps died from natural hazards, hence the nickname Jinx.
• She was an outcast in her society, most of her peers would have Taken the other path to adulthood, suicide.
• She, along with Brightspot to-Srallansre, accompanies the Enterprise crew first contact team on their own Walk so that the other Sivaoans will treat them as adults and provide urgently needed medical information.
• During that Walk Chekhov comes down with ADF syndrome (which turns out to be a childhood disease known to her as Noisy Baby) and the walk must seemingly be aborted. She reluctantly swears to the team that she will not take her life in order to guide them to safety. Risking permanent exile from her society.

• After unexpectedly completing the Walk with James T. Kirk, she chooses Another StarFreedom to-Eeiauo as her adult name.
• She accompanied others back to the planet Eeiauo to help her kin that were afflicted with ADF syndrome (TOS novel: Uhura's Song)