Princess Nuala is the Elf Princess of the Bethmoora Clan, the only daughter of King Balor and Prince Nuada's twin sister.
Opposite to her brother, Nuala is a gentle creature who desires peace and also possesses psychic powers. She is one of the supporting protagonists of Hellboy II: The Golden Army and Abraham Sapien's love interest.
Nuala is the twin sister of Prince Nuada. When the realm of magical creatures was threatened by humanity, a golden army was created. After much slaughter, the elf king agreed to a truce with the humans.
The crown that controlled the golden army was split into three pieces: one for the humans, one for Nuala and one for the king. Nuada would go into exile.
Centuries later, Prince Nuada approached Nuala and their father in an attempt to revive the golden army and destroy the humans once and for all. Nuada had obtained one piece of the crown and gained the other by killing his father. Nuala fled, taking the last piece with her.
Nuala ran into Abe Sapien, who like her had empathic powers. Abe developed strong feelings for her and offered her refuge within the BPRD. Nuala warned Abe that her empathic powers allowed her twin brother to read her mind, meaning he would know where they are.
Nuada found them, kidnapped Nuala and mortally wounded Hellboy. Abe, Hellboy, Krauss and Liz travelled to Ireland to confront Nuada. Abe provided Nuada with the last piece of the golden crown in exchange for Nuala's safety.
Nuada summons the golden army and would have killed them, but Hellboy challenges Nuada for the right to command the army. Hellboy wins, but Nuada tried to stab him when his back was turned.
Nuala managed to stop her brother by stabbing herself, the damage being transferred directly to Nuada. Both died, but not before Abe let Nuala know his feelings for her.
Princess Nuala is the opposite of her twin brother, Prince Nuada. She seems light, compassionate and fragile where the prince is sinister and unyielding.
Nuala seems more silent and inactive compared to her father and brother which may stem from being raised in a society not offering females the same voice as males.
She does, however, display assertiveness when confronting Abe Sapien and even threatens him with a knife, refuses to part with the crown piece and also actively defies her brother's schemes, showing she is not entirely submissive.
Her brother has a great deal of respect for her and seems to value her opinions and feelings as much as his own while not changing them.
It is unclear whether or not Nuala is older or younger than Nuada (by a few moments at best) and she does not seem to have any significant claim to the throne. She bore one of the three pieces of the crown of Bethmoora from her father, King Balor.
This is unusual considering that she seems to not have any power in court which would justify her having the piece (tradition dictated that it should have gone to Nuada, but it was likely denied to him because of his hatred for humankind).
Nuala appears to be a pacifist and, at the bequest of her father, would rather fade away into obscurity and nothingness rather than stand and fight against the evils of man.
Her view toward her brother's insistence on this is one of pity and shame, but she seems to have a great deal of respect for his courage. Nuala also shows an appreciation for art and literature in the film (in reading Tennyson aloud from an anthology of 'In Memoriam').
She seems to be more accepting and remembering of the natural world when the forest entity is destroyed and its floral remains are spread. Nuala fates herself to die in order to keep her brother from killing Hellboy and continuing to seek for humanity's destruction.