Deceit
We watch as King Gunther deceives Brunhild into believing that he defeated her to win her hand in marriage, even allowing Siegfried to become him with the invisibility mask to subdue her with his strength. And, once Brunhild learns of the King's deceit she plots her own and tells him Siegfried stole her maidenhood from her thus setting in motion his death.
Betrayal
Betrayal is a major theme of this film, particularly betrayal of loyalty and of vows. King Gunther betrays his loyalty to his friend, Siegfried by allowing Hagen to kill him instead of going to his friend to find out the truth. We also see the betrayal of Kriemhild twice. She reveals to armlet to Brunhild she promised never to show to another human eye, and she marks Siegfried's place of weakness for Hagen to kill him.
Revenge
Hagen, who believed all along that Siegfried should not be a royal, uses the man in order to get what he desires, which is more glory for the King and thus more power for him. As Siegfried grows in the minds of the people Hagen plots to have the man killed in order to get revenge upon him for bringing the status of the King lower. Brunhild is also out for revenge. She cannot believe that she was defeated by the King and thus seeks every day to find the truth of how she was defeated. And, when she does she sets out to destroy everyone, including the King as she takes her own life so that he won't be able to have her by his side ever again.
