Emily was conceived in the Dream Plane of D'zeron, and is a Chosen One of HomeWorld, thus she is able to call or send away Gaia . Because she is a descendant of Emily Hawthorn and is a Chosen One, she is able to at will grow butterfly wings and fly, which is very disturbing to her father, as she manifests this capacity when she is very young.
She is a cute curly blond haired little girl, and spends alot of time with her daddy. She is very spoiled, but in spite of that is a sweet girl who gets along well with everyone. She is the center of Daddy's world, and travels with him whenever he returns to Paragangia. Serai and the other children remain in D'zeron.
As a young woman, she calls Gaia and chooses to be assimilated by him, leading him to believe she is choosing to join him, giving him the spirit of a chosen one and thus freeing him from the control of the Chosen Ones. Emily then defeats Gaia from the inside: Being a Chosen One, her spirit is more able to control the Leviathan body than Gaia's normal human spirit. She casts the Spirit of the man Gaia out of Leviathan, thus killing Gaia, and then she releases all the spirits held captive in Leviathan by Gaia. She remains the only spirit inhabiting the monster Leviathan, and is therefor more or less dead as a human. The body of leviathan cannot die and she does not know how to remove her spirit from it. Although she is in a sense still alive as the monster Leviathan, Jason is devistated by her loss. [I have not thought about what you would do after that
Even though they have several other children, Emily is always his favorite, and the other kids might well resent this. I haven't created any other kids yet, but I think they will have three more. Probably two more girls and then a boy. The boy would be born much later, perhaps after Emily is lost, or around the same time [Serai is very young when Emily is born and Emily is probably only about 16 at the time she defeats Gaia.] Serai might die in childbirth. This could spark the Depression which causes Jason to go off with Carston. He would blame himself for the death of Serai, since she conceived the boy to comfort him because he missed Emily so much. Thus he would miss most of his son's childhood, or he would choose to return when the son was too young to have missed him too much, but Jason would be much older. Perhaps Jason would then raise this son alone in D'zeron. He would allow himself to be healed with Paragangian medicine, partially giving up his retrotechnology Ideal in his old age. When the son is grown, he might leave D'zeron and go live on the New Paragangia. He might marry again in Paragangia and leave Paragan children. [or he might prefer to die in D'zeron so he could be with Serai]
It might be possible under some circumstance for them to meet again in the dream plane.
I do not know what the implications are for Emily as a Chosen One. Since she sacrificed her own mortal life to free the spirits of others, I would not think she would be punished for this choice, as it is a christlike sacrifice to which she was destined. I might have to write a sequal to this explaining what happened to Leviathan after this, and how Emily is eventually freed from it so she can move on the the next rhelm of existence.
Carston's lifelong quest [in the Gift of Time Series] was to free his wife Sharae from Gaia, Emily effectively does this by releasing all the spirits taking captive by Leviathan. It is realizing that Emily has to exist for Sharae to be freed that inspires him to kidnap Jason and force him to create the conditions for his own existence and the existence of D'zeron and Serai, Hence, Emily. Thus in his journey with Jason as the creator of D'zeron Zenneth is his way of saving Sharae.
In the end of the time traveling journey that he takes Jason on at the end of his life, perhaps Carston will help defeat Leviathan and free Emily's spirit from it.