Siegfried, I thought, represents what the Germans want to achieve, heroically to impose their will, have their own way… The dream showed that the attitude embodied by Siegfried, the hero, no longer suited me. Therefore it had to be killed.
Jung interprets the dream-assassination of Siegfried as the necessary sacrifice of heroic ego-will and the ideal of forceful self-imposition, marking a decisive psychic turning point.
, Jung on Active Imagination, 1997thesis