The pirate-garbed space nomad who is the captain of the Cosmic Hound.
Portia is a native of the planet Aquaterra who leaves her dying home with the intention to die alone in space. However, the seemingly "barren planet" she chooses to end her life on is actually the home of the Cosmic Hounds, a race of telekinetic canines. Captured and mutilated by the hounds, Portia is kept a prisoner, forced to ferry her captors through space aboard her ship for over 300 years. Although the hounds extend her life beyond its natural span, Portia nevertheless craves the peace of death.
Eventually, she is able to lure Superman through a "weird hole in space" and into a confrontation with the dogs, who are able to temporarily defeat the Man of Steel due to the baleful effects of a vapor-cloud. Recovering, Superman frees himself and Portia from the influence of the dogs and returns the alien woman to her home planet, in the process discovering that "radiation from a a freak flare-up of Aquaterra's sun annihilated its life-forms" many years ago. Removed from the dogs' telekinetic ability to "cause the cells of [her] body to regenerate," Portia quickly ages. As she dies, her former captors appear and cast a force field about her, preventing Superman from interferring in her long-postponed natural death (S No. 318, Dec 1977: "The Wreck of the Cosmic Hound").