Nadja is a young girl with short purple hair that stops above her shoulders. She wears a full length dress with long sleeves and a decorative collar with a brooch and earrings.
Her appearance is almost identical to that of her niece, Veronica.
Nadja is a kind girl who loves to read, her favorite books being adventure stories. This could be because of her frail body that stops her from going outside the castle walls. She is also very caring and accepting, this is shown when she brings Gowther a present. She also still accepts him and cares for him, even after finding out he is a doll.
45 years ago
Nadja was the sister of Bartra and Denzel Liones and the princess of the kingdom of Liones. She met Gowther after hearing one of her brother's visions about a person in a cavern underneath the castle. She went and explored herself, coming across Gowther who seemed to be waking up from a long sleep. She screamed in surprise when she first saw him due to being surprised by him appearing in front of her, though calmed down and began asking him questions and telling him where he was. When she headed back to the castle, she promised Gowther that she would return, comparing his excitement to that of a child's. She excitedly told Bartra about Gowther when she returned to the castle. Despite being happy for his sister, Bartra was worried about her due to her heart condition.
The next time Nadja went to visit Gowther, she brought her favorite stories, telling him that she spent a lot of time reading due to her poor health. She was surprised when Gowther told her that he had finished the book after quickly skimming the pages, and was further shocked when Gowther showed his shape-shifting abilities by demonstrating the heroine's long hair and how he was confused by how she could fight with the helmet getting in the way of her hair. She passed out when Gowther revealed himself to be a doll and showed her his heart. Gowther brought her back to the castle, and, refusing to be alone, dressed like a maid to be brought into the castle after Bartra provided him such clothes. Nadja was annoyed by the outfit and told Bartra not to convince Gowther to cross dress.
Nadja and Gowther began having a close relationship, always being together, a fact that the guards and her family noticed. Their relationship was to the point that at one point, Bartra pulled Gowther to the side and told him to stay with his older sister, to which the doll agreed. At some point a bedridden Nadja was alone with Gowther in her room, where she remorsefully admitted to Gowther that her heart condition was getting worse, and that soon, she would die. This revelation left Gowther devastated, but the princess began to open her heart to Gowther and express her feelings, to which the doll reciprocated. Sharing a kiss, the couple undressed and proceeded to make love. Nadja would quietly pass away that night in her sleep, a peaceful smile in her face as her dream was to spend her final moments with Gowther.
The following morning, Gowther woke up to find Nadja dead, which left him in a horrified panic. In an attempt to save her, Gowther removed the heart inside of his chest to replace Nadja's with, tearing her chest open in order to do so. His distressed cries alerted the guards outside of the room, who burst in to discover a bloodied and naked Gowther on top of Nadja's unclothed body, mourning about how his heart had failed to revive her. The guards mistakenly considered that Gowther had raped and killed her, thus leading to his arrest and eventual death sentence by immolation.
- Nadja's love scene with Gowther in the anime did not include the sex scene, instead having Nadja pass away as she rested her head on Gowther's shoulder. The guards assuming that Gowther sexually assaulted Nadja came from how Gowther had opened his shirt to pull his heart out, as well as opening Nadja's gown to open her chest.