IQ: 240+ (pegged a non-verbal IQ test)
Physical description (at start of story cycle): 5 foot 11 inches tall, Caucasian, straight black hair, very light grey eyes, oval face, hair to small of back, pale ivory skin. Sedentary. Had bariatric surgery two years ago, now weighs 120 pounds. Angelic beauty: her eyes can stun a man in his tracks, and her face holds an echo of an unfallen humanity.
Orientation: bisexual female, chaste virgin
Celestial representation: Venus.
Likes: uninhibited and passionate lovemaking with her husband, Martin
Special Talents: intellect beyond human comprehension, perfect mind-body coordination
Paranormal abilities: none
Relatives: Martin (husband), Marvin (son), Alouette (daughter), Robert (father-in-law), Sylvia (mother-in-law)
Advisors: Martin (husband), Margaret (other self)
Friends: Martin (husband)
Occupation: organic supercomputer for Margaret's imaginary heads-up display
Star Child is the pet name Martin gave Margaret for her hidden depths tucked away in the young lady's subconscious which provided her extraordinary mathematical and other intuitions. However, those intuitions turn out to have life and desires of their own. Star Child is the original Margaret from birth. This little girl was badly traumatized on at least two occasions: first, for being abandoned by her parents at 3 for having autism and aphasia, and second, during 4-5 being practically tortured into learning how to talk through experimental sensory bombardment. The trauma caused a personality split. As time went on, Star Child took her cue from watching movies to shape the chipped-off fragment of her personality into the psychological equivalent of invulnerable armor and designates the lesser personality to behave analogously to the armor's artificial intelligence. Star Child hid behind that and waited for the day when she could be unconditionally loved for exactly who and what she was. In the meantime, she powers the armor that is Margaret, costing her about 80 IQ points, which is why Margaret only has a 160 IQ: good enough to survive on, but not nearly the entire girl's abilities.
Margaret revealed to Martin she had autism minutes after they first made love, and he assures her that he loves her regardless, and invents the pet name "star child" for her on the spot, alluding to Margaret as a Monolith (TMA-2) and her depths deserving that name as what he experiences by being the first to dare encounter that monolith intimately.
Star Child chooses that moment to temporarily emerge from Margaret and reveal her pent-up pain. He holds Star Child in his arms and allows her a screaming tantrum where she also is sobbing and pounding her fists on his chest and shoulders in rage against humanity's lifelong coldness toward her for her condition. When she finally calms down, Martin has by now earned the love of both halves of this girl. In his care she may even get the chance to heal. Star Child, with her heart now won, decides Martin deserves something he would understand as wonderful. Working as Margaret's imaginary mathematics heads-up-display she awards him, and through him a humanity she's now convinced is worthy, the gift of faster-than-light travel.
Margaret deduces the existence of a personality kept hidden with a post-hypnotic aid from her therapists at the hospital, a stuffed cat. Margaret always reboots when the doll is the first thing she sees, and deduces that as the reason why the therapists cautioned her to keep the doll with her. Margaret decides to leave the doll behind on her wedding night, she tells Martin she'd rather consummate the marriage in the morning after a good night's sleep, and explains she'd rather have her inner self made love to first by him.
Martin eagerly awaits Margaret as she takes her turn in the motel bathroom, but notices her behavior is completely different, almost naive. She's also silent and does not seem to understand words. At this point he concludes his wife's hidden depths have a reality and personality of thier own, that there really is a "Star Child" lurking underneath Margaret, standing before him now eagerly waiting to be held and loved; just as he suspected there might have been while he was facing an uncharacteristic fit of rage after expressing his unconditional love for Margaret. He therefore formally welcomes this side of the girl by this "pet name".
What follows is an extremely cleansing experience for Star Child. Because Star Child being unable to speak or understand words is the unfallen half of Margaret, the experience is powerfully moving for Martin: while Margaret is great at technique and loves to take charge, Star Child is loving and sweet in a primal sort of way. Star Child naps afterward, and upon waking is addressed by Martin as Margaret, causing that side of her to reboot. Evidently the therapists implanted this emergency backup in case the doll ever got lost.
Once Star Child discovers she is pregnant, she realizes she is obsolete, and fades into Margaret to become a whole person with Margaret's personality intact, but also the intellect she was born with. She even has all of Star Child's memories with Martin, and proves it by making love to him the way Star Child would. Still, something rare and precious and wonderful had left the universe when Star Child decided to pass away.