It is in the first book, Vampire Academy that the Queen is first introduced. The first time that Rose meets her, she brutally insults her ' Royal Highness' with a bunch of snide retorts. It was Tatiana who insulted Lissa with a bunch of remarks that she wasn't living up to the name 'Vasilisa' nor the Dragomir reputation after she had returned after fleeing Saint Vladimir's the prior year, purposely humiliating Lissa in front of the whole school.
In the third book, Shadow Kiss, Tatiana thoroughly 'bitches' Rose out for her rumored relationship with Adrian, her great nephew.
In the fifth book, Spirit Bound, Rose and Tatiana are apparently at complete opposites. After Rose, Eddie, and Lissa return to the Court after freeing Victor Dashkov(although they are able to hide their involvement by claiming that they were partying in Las Vegas, supported by video footage) Rose and Eddie are sent to administrative duties while Tatiana lectures Lissa, but does not punish her. However, she is now able to plant her own loyal guardians to Lissa. Later, she has Rose come before a council meeting, where she questions Rose on her past accomplishments at Saint Vladimir's. Believing that the meeting is an evaluation of her, Rose boasts of her past accomplishments, believing that this will be an end to her recent labor work. However, in truth, it was a meeting to lower the age of Dhampir becoming Guardians to 16. Rose is enraged at the realization that Tatiana tricked her. Later on, Tatiana holds a large meeting to explain her decision to lower the age. However, Rose, still livid, confronts the Queen in open court(despite a desperate plea from Lissa not to do so) and tells her that she is wrong. The Queen, calm, counters Rose by stating that Rose is currently slated for an administrative position, but she could change that with Rose's support(Essentially threatening Rose by stating that if Rose does not support her, she will have Rose permanently on desk duty for the rest of her career.) Rose, furious, refuses the queen in front of everyone, saying that she will never accept any offer from her, then calling her a sanctimonious bitch, finally breaking the Queen's calm facade(and essentially destroying any Guardian career Rose dreamed of), and causing chaos to erupt in the court.
Tatiana is later murdered. Rose Hathaway is the main suspect for this murder, due to several factors, such as her argument with Tatiana in court and that it was her stake used to kill the queen. Before her death, Tatiana wrote a letter to Rose, explaining that Lissa Dragomir's father had an illegitimate child and that Rose must find him/her.
To many in her family, she is known as being prickly. Especially in Adrian's mother's case. Who happened to be sharing a lover with the queen, Ambrose.
She has mixed feelings about Moroi fighting, having secret training sessions by Grant, one of her Guardians. She claims that "what she did for the dhampir community was better" than what others requested, changing the law to release dhampirs at age 16. However, in truth, this was merely a stalling tactic to stall others in Court who had more extreme ideas about dhampirs.
Rose Hathaway was framed for Tatiana's murder in a bid to rid her from the Royal Court and even have her killed. However, Tatiana was murdered by Natasha Ozera due to their conflicting ideals, and framed Rose for the killing after becoming extremely jealous that Dimitri Belikov was in love with Rose, and not her. Tasha was eventually found guilty and convicted of murder, losing both her freedom(and later her life, as all royal traitors are executed) and any chance at a friendship with Dimitri.
Tatiana loved and adored her only great nephew, Adrian Ivashkov. As Adrian states that she was the only one not to deem him as a failure, and made him feel loved. They used to smoke in the throne room when they were alone, Tatiana in returned called Adrian "her little artist" showing that she believed in his talent; the only fault with the relationship with that Tatiana wanted Adrian to marry Lissa Dragomir but he refused. When Tatiana was murdered, Adrian had been seen drinking and smoking more then normal and also sent him in deep depression. It is later found out that Tatiana had given Adrian platiunm ruby clifflinks, to which Adrian says he would be living on the streets, dying before he gave those away. She also is seen to have conversations with Adrian when in a Spirit Darkness moments.
Neither Rose nor Tatiana loved their relationship, especially Rose who was in shock when she received the letter from Ambrose about Jill. Much of their relation was filled with Tatiana's wrath over Rose's relationship with her great- nephew who she secretly wanted to pair with Vasilisa Dragomir, and Rose was furious over Tatiana's decree lowering the guardian age to 16. However she trusts Rose enough to tell her about Lissa's half-sibling in a note, knowing that Rose would do the right thing with the information.