Due to Siegfried's nature as someone who did as he asked without question, he was involved in the dilemma between his brother-in-law, King Gunthur, and the woman Gunther desired, Brünnhilde. As the various circumstances came to a head, Siegfried was left with no choice but to die to stop conflict between Brünnhilde and his own wife, Kriemhild. He exclaimed to his friend Hagen, “Ah, the situation is beyond my control. Hagen, I am invincible and so have never once been wounded by you. But even so, if I don’t have you kill me…”
Hagen sought to grant Siegfried's wish, having formulated a plan to slay him after having tenaciously searched for Siegfried's weak point. Though he knew it was a cowardly act, Hagen aimed for Siegfried's back as he drank water from a stream, Siegfried himself not resisting the blow. He died as a "tragic hero who received a sneak attack due to trickery." Hagen became known as "a rare villain who had killed the hero through foul play." The situation after did not go as Siegfried planned, his wife later causing many to die in her revenge plot.
Hagen appears in Siegfried's second Interlude. Das Rheingold, Siegfried's Noble Phantasm, is summoned into a Singularity after the final defeat of Fafnir. Due to Hagen's connection with the treasure, having obtained it after killing Siegfried, he is summoned into the world. He claims that it is his treasure, insulting Siegfired and Kriemhilde, and battling Siegfried and his Master, Ritsuka Fujimaru. He reveals after the battle that he was simply venting his anger at Siegfried's end, not having actually cared about the treasure.
- ↑ Fate/Apocrypha - Volume 3