Drusilla was born in an area of Earth called the Exterior. It is a place where people who don't want to abide by Earth's current governmental restrictions can go and live. It's unclear what these government restrictions are, but Drusilla wanted to leave and when she was 16 years old an opportunity to leave presented itself. However, leaving was not as easy as just booking a plane ticket out of the Exterior. She needed to escape from the Exterior when her mother would not notice.
Her mother was a local healer or witch for the Exterior and Drusilla as well as her siblings all possess some supernatural qualities, for example, Drusilla is telepathic. It's unknown who Drusilla's father is for much of the series until it's revealed in the final book The Disciple of the Alien Goddess of Home.
In Book 2, Married to the Alien Doctor, Drusilla goes directly to a guard house a the edge of the forcefield separating the Exterior and the rest of Earth, believing that if there were only a few guards there she could use her telepathy to trick them into letting her leave. We find out later in the book that supposedly people from the Exterior were allowed to petition to leave, but Drusilla had never heard of anyone doing that. When Drusilla reached the guards gate there were more men there than she thought there would be so she made a naive deal with them that only one unfamiliar with intimacy could make. This experience had a profound impact on her life and it was only when she reached the Alliance Empire did she begin to receive some advice and medical attention for it. This was because Alliance doctors are all telepathic and Drusilla was unable to hid what always haunted her in her thoughts. Also for the Alliance which was suffering from a demographics issue and needed healthy women, it was in their best interest to make sure that all the young women coming to them were healthy and had normal sex lives as the Empire was concerned about the cultural impact of using humans to solve their problem of low number of females being born.
As Drusilla was telepathic and had held the rank of a Junior Doctor on the Starship Dakota under Captain Rainer, she wanted to continue to be a doctor and when the rest of the human women, abducted from their ship, joined the Alliance Fleet, she alone stayed on the Alliance Capital Planet to pursue becoming an Alliance Doctor.
Without a doubt live was difficult for Drusilla from the beginning. She did not have a good relationship with her mother who she was an apprentice to in the Exterior. When she ran away to the Earth Fleet she didn't realize until too late that 16 years old was too young and had to lie about her age and also hide that she was telepathic and so it really wasn't until she moved to the Empire that she found her true self in terms of work. She took to Alliance medical school like a fish to water and despite her starting late (she was offered a mental download of information which she took and a private study room a the library bought by her then suitor and later husband, Ket of House Vo), she excelled and graduated the first in her class. Alliance women at the medical school had mixed emotions about a human among them and she faced some racism but this never managed to decrease her professional success. After graduation she took a job at the most prestigious hospital in the Empire, the Capital City Hospital.
Drusilla becomes a very religious woman and proclaims herself to be the disciple of the goddess of home from book 2 when she makes a deal with the said goddess. Her husband, Ket, is also religious, and it becomes apparent throughout the series that they are leading a kind of conservative movement back towards the old ways of the Empire which many people find threatening and repulsive.
Drusilla had a ban put on her very early on in her days in the Empire. She had no idea that this had been done to her as she was at most times, the only human on the planet besides Frank and his wife Zelda who own the Earth Store. However, they were not a source of cultural information about the Empire as they lived as outsiders in the immigrant ring of the Capital City.
The ban, which is seen as a very romantic gesture among Alliance people, seemed cruel and archaic to Drusilla. Who in the middle of a prestigious Assembly accuses Ket of House Vo of embarrassing her in front of the entire Empire by putting this secret ban on her and not saying who he was until that night. Fortunately for Ket, he had already formed a relationship with Drusilla so they could reconcile and later marry.
Drusilla had issues with the Alliance custom of men in the fleet being able to have sex with slave artists while outside Imperial Territory and she made Ket take a vow that is genetically linked to her not to have sex with anyone but her. If he tries, he will pass out. The same will happen with her if she tries to be intimate with anyone else besides Ket. These genetic promises are marked on the holders' wrists with tattoos called 'binding tattoos.' They are a very old tradition in the Empire and at first Ket is very hesitant to promise this because as he understands it, not having sex at least twice a week can cause mental illness. However, Drusilla insists.
Ket and Drusilla use IVF which is forbidden in the Empire to have the first daughter born between an Alliance and Human. In later books, Drusilla's sister Julia, better known as Jesse, is the only one to have figured this out and keeps the information as something to hold over her sister just in case she needs it.
Later Drusilla becomes pregnant with another child. It's unknown if this is from IVF or not, but probably not. This child may be the reincarnation of Jane Johnson if we are to go by signs in the final book, The Disciple of the Goddess of Home. We will have to wait and see when the first book in the new series comes out, Eternal Harmonies, and see who ends up being mother to the reincarnate Jane Johnson.
Drusilla has very few friends and we know that a lot of the other human women find her odd. Ironically, Kara Rainer is a true friend to Drusilla throughout the series until the end. Even when the two women are dueling, Kara holds no resentment against Drusilla for killing her as she would do the same if their roles had been reversed.
Drusilla is also close with her mother in-law and particularly her sister in-law who she met at medical school.
Drusilla has no reason to want to challenge anyone to become Empress, despite what is going on around her. She has never been a leader nor has she ever been a good friend to anyone. Even in her relationship with Jane Johnson, it wavers when she finds out the deal Jane made with Dr. Anu from Space Station One and the 1,000 women brought over, how their eggs were harvested with random human men's sperm to create embryos that were subsequently implanted into Dulu wombs illegally. And despite Drusilla treating her own sister pretty terribly, when the first human Empress Kara, threatens her sister's life over almost nothing, in Drusilla's mind, Dru feels that she must do something. And it's only at that time, that she picks up her feeling that actually she is doing this, becoming Empress for all humanity. She has a rage within her that we only see for the first time when she is dueling Kara, Drusilla's conflicting emotions about her love for the Alliance and the Empire for the recovery and its ability to heal her and make her whole, but also the hate for the cost that she had to pay to the Empire for that healing. In the end, it's destiny that wields these women's fates and when Kara dies it is obvious that she and Tir had been only destined to play their role and then leave. That Drusilla was meant to be Empress by the God of War but she would have never been able to achieve that without Kara's sacrifice.