Her mother, Marianne, stepped down to mourning the loss of her husband, the previous king, as she did not have the heart to continue to rule Tristain after his loss.
Henrietta has two cousins: Tiffania and Wales. She and Wales were lovers (despite them having a blood relationship), but he ends up being murdered. She has vowed to love Wales forever, even though his dying wish was that she would fall in love with another man. He simply wanted this so that she could be happy. In the novels, the canceled wedding of Henrietta in Vindobona.
Later in the series, Henrietta seems to develop feelings towards Saito. Though at first, she doesn't even realize it. Once at the Slepnir ball she disguised herself as Louise because she envied/admired her childhood friend's strength to do what she has decided on. Henrietta also confessed to Saito she loves him then, and Louise found out when she kissed Saito. The next day after Louise was rescued from Myoznitnirn's grasp Louise confronted Henrietta and the queen apologized to Louise. Louise then slapped Henreitta for trying to steal away her familiar, and declared if the queen wants to go between them she better have the resolve to fight for Saito. Henrietta was surprised by Louise's vehemence but understood.
In Volume 16, Saito discovered his mansion had a portal leading right to Henrietta's bed chambers, and they discovered Saito's mansion houses a secret room for the Tristain monarch to meet up with their mistress, but haven't been used for a few years. Henrietta and Saito confided in each other about the current political situation of Tristain of how she should marry someone stabilize the political situation, with Saito saying if she's not comfortable with marriage she shouldn't have to go through with it. Henrietta admitted she still could not push Saito away from her kind, seeing as he's the only one that sees her as another person without things like social status getting in the way of conversation. The two of them kiss, with Saito unable to reject Henrietta's feelings, and Louise found the two of them like that.
Within the Queen's bedchamber, there resides a mirror capable of transporting a person between her room, and a hidden bedroom in Des Ornières. When Saito touches the mirror, he sees Henrietta image on the other side. When Henrietta says Saito name she find herself on his side of the mirror. Saito and Henrietta find this passage, and temptation leads the Queen to forget her courtesies and kisses Saito. Henrietta think it was her father magic used on the mirror for his mistresses and him to meet. Henrietta even going as far to offer meeting again, Saito declines declaring his continuing care for Louise. Later, Louise and Siesta board up the mirror with the reluctant help of Saito. Louise tells Siesta that evil spirits will come through if they don't block it.
Louise then ran away, thinking it would be best for those two to get together instead of Saito staying with her—She thought it would be better this way as she thought she could not be a match for Saito anymore now that he's a war hero, and his accomplishments outweighed her own in her own view.
In Volume 17, Henrietta and Saito tried to track down Louise, but to no avail. Colbert and Kirche started to suspect something might be going on between Saito and the queen, and Colbert didn't want to consider the political fallout.
After Louise eventually came back to stop a Gallian assassin from killing Saito, the two of them reconcile. Henrietta looked on and decided she won't get between them anymore, though this resolve won't last.
In Season 4, Henrietta sends Saito, Louise, and Tiffania to Romalia to meet the Pope and herself in order to discuss upcoming dangers for the kingdom and the need for their services. Later, in a private room, Henrietta gives Tiffania the ring of Albion she received from Prince Wales. She felt that, since Tiffania was the only living member of the Albionian royal family, she was the rightful owner.
When an Ancient Dragon dared to kill all the void users and was heading towards Tristain. Henrietta brought her allies to destroy the beast. Queen Henrietta and all at once shoot the Ancient Dragon with their ships cannons. The Ancient Dragon shoots a blast at their fleet, the fleet is saved when suddenly Bidalsha and his elvish army uses ancient magic to suck in the fire into one of the fire ball. After the dragon is killed, she attends Saito and Louise's wedding.
Also Known as
- Queen (by Agnes)
- Princess (by Louise and Saito)
- Your Majesty (by Louise and Saito)
- Your Highness (by Agnes)