Nimue the Queen of Blood is a villainess in the Hellboy comics. A powerful sorceress, Nimue lived during the reign of King Arthur. Due to her power, she was imprisoned by the witches of Britain for 1500 years before her revival to lead the Wild Hunt.
In life, Nimue was loved by the wizard Merlin, who told her all of his secrets. However, Nimue betrayed Merlin and eternally imprisoned him alive inside of his grave. Driven to madness without Merlin to guide her, Nimue began to worship the Ogdru Jahad. Nimue was killed by the witches of Britain and her body pieces scattered across the Earth, but they would always rejoin, prompting the witches to imprison her inside a wooden box and burying her within the Earth.
1500 years later, the witches of Britain, seeking a new leader, eventually agree to nominate Nimue. The fairy Gruagach, assisted by his companions and a giant overseeing the seal, released Nimue's box. Sometime after, Gruagach was approached by Astaroth, who helped release Nimue. Upon her release, Nimue ordered the witches of England be murdered, and demanded an army be marshaled for her. Nimue promises to make Gruagach strong again and will deliver Hellboy to him when the time is right.
While Nimue waits for her army, an ambassador from Uddsvick, the king of Jutland, arrives and relays the message that the kings of the north will fight for her. However, Nimue then tells the ambassador to kill the king and fashion an iron helmet from his heart. Some time later, when an impatient Gruagach demanded that Nimue make him strong, and suggested that she lacked the power to do so, she cast him away and vanished with her followers.
Nimue later murders Queen Moab and uses er blood to empower a fairy under her service in order for her to kill Hellboy. Nimue then raises her army to go to war, opposed by undead British soldiers. Nimue is revealed to have been used by the Ogdru Jahad as a vessel and possessed by them, resulting in her transformation into a dragon-like creature that attempts to kill Hellboy. However, Hellboy ultimately kills Nimue with a sword given to him from Vasilisa. Nimue is dragged into Hell by Britain's witches, but she refuses to face condemnation alone and removes Hellboy's heart so that he will perish too. Nimue was imprisoned in Hell afterwards.