Debra inhabiting Hemmer
"She was lonely. Like me."
Debra was the name given to an alien consciousness that resided in the Jonisian Nebula in the 23rd century, theorized to be a Boltzmann brain.
In 2259, as the USS Enterprise concluded a routine survey mission of the Jonisian Nebula, the entity (that would later be called Debra) brought a version of the fairy tale The Kingdom of Elysian to life from the mind of Doctor Joseph M'Benga's daughter Rukiya. Rukiya was later offered the opportunity to stay with the entity, naming her Debra after her mother. (SNW: "The Elysian Kingdom")
Debra was played by Bruce Horak when she inhabited Lieutenant Hemmer's body, and was voiced by an unknown actress.