- "I would give my life to see such a marvel!"
Seigfried was a German youth, groomed for spiritual purity by his father, Dieterhoffmann, who led an effort to reclaim the Spear of Longinus for Nazi Germany. He is frequently referred to as Seig by his father and his father's enemies alike. He exemplified the Nazi racial ideal of the Aryan: handsome, blonde, and strong.
During World War II, his father began the search for the Spear of Longinus and recognized that it could only wielded by someone virtuous and pure of spirit. He began grooming Seigfried for this role, by keeping his son isolated, so that Seigfried would not learn about the evils being committed by the Nazi regime, but instead focused on prayer and mysticism.
In March 1945, Seigfried accompanied his father and several colleagues to Glastonbury in the United Kingdom to attend the annual conference on Holy Grail lore. They met with Professor Henry Jones to see what he knew about the Spear of Longinus. Seigfried was unaware that his father was in the process of acquiring the spear tip through contact with Otto Nehrkorn of the museum in Nuremberg. Professor Jones considered Seig as a would-be mystic, more interested in seeing the sacred relic than wielding its power.
Seigfried received a note from the professor, inviting him to meet privately at the Chalice Well to share some lore on the spear. Seigfried arrived at sunset, and while waiting for Jones to show, he drank from the spring's holy waters. While imbibing, he pondered about the nature of the spear, and received a vision of himself as a knight, and a medieval king explained that the spear flowed blood in sorrow, but the blood itself would purify and heal. Jones' arrival ended Seigfried's vision, and Jones' alluded to Seigfried's talk of blood purity in relation to Adolf Hitler's views and acts in the war. Not understanding, Seigfried attempted to flee, but was tackled by Brendan O'Neal and questioned by Indiana Jones - the meeting with the professor had been a trap!
Seigfried fought with Indiana and his assistant, and professed no knowledge of the spear tip's whereabouts. Professor Jones believed the boy's innocence and offered to release him. Dieterhoffmann arrived with his men and captured the Joneses and O'Neal. Dieterhoffmann explained that he had kept his son in the dark regarding the more sinister acts during the war, and had Kurt and Jorge tie up the younger Jones and O'Neal. With Nehrkorn's arrival, Dieterhoffmann revealed that he now possessed the tip of the spear, much to his son's amazement, and that Seigfried would wield the spear to restore Germany to its glory, something that the Austrian-born Hitler could not do. After ordering the deaths of his captives, Dieterhoffmann commanded that his son return to the hotel, to avoid witnessing the violence.
The executions were halted when a tour of schoolgirls walked into the area, guided by a botany teacher, teaching about the garden's plants. While the teacher tried to shoo away Dieterhoffmann as a trespasser, several of the girls, including Sally's friend, expressed an interest in the attractive but shy Seigfried. After the girls reassembled for their tour and Indiana Jones escaped, Seigfried objected to his father furtively drawing a pistol on Professor Jones. Indiana Jones rushed back, knocking into Seigfried's father. The pistol went off, and the shot split the spear tip - one half of which landed in Seigfried's hands, and the other half ending up in a freed O'Neal's possession. The Joneses and O'Neal escaped.
Seigfried accompanied the rest of the Nazis in a car chase from Glastonbury into Wales, where they captured Professor Jones and his getaway driver, Rebecca Stein near Gorsedd Arbeth. Indiana Jones was also captured, and Seigfried objected to his father ordering Jones' death by having him tied to a boulder and dropped into a lake. With their captives, the party traveled to Holyhead, where Dieterhoffmann's thugs helped to commandeer the ferry to Ireland.
The appearance of O'Neal appeared on the upper deck of the ferry bought a moment for Professor Jones to escape, and for a wet Indiana Jones to sneak up behind Seigfried and hold him hostage with a knife to his throat. Unwilling to endanger his son, Dieterhoffmann threw the spear tip bundle to O'Neal, and ordered that Jones release the lad. Seigfried realized that Jones was not a killer and told his father not to give in to Jones' demand to free Stein. Realizing that his son was right, Dieterhoffmann sent his men after Jones, but O'Neal tossed the spear tip bundle into the waters, giving time for O'Neal to escape, and Jones to unsuccessfully attempt to free Stein from Kurt. With the spear tip bundle recovered, and only one hostage, the Nazis took the ferry across the sea, using a Nazi submarine as escort.
Regrouping at Connely's Inn with the his father's allies among the Blueshirts, Seigfried now wore a white Nazi uniform. His father, who was already enraged at having lost half the spear tip to Jones again, struck Rebecca Stein down for goading him, Seigfried spoke out against his father's violence to their unarmed captive. His father hinted at Stein's Jewish ancestry and realized that perhaps he had kept his son too pure in keeping some of the Nazi racial ideology from him. Seigfried helped Stein regain her feet as Indiana Jones appeared upstairs, taking one of the Blueshirts hostage in trade for Stein. Dieterhoffman refused to trade, claiming that the young man was not one of his. Connely objected to the Nazi's lack of protection, but Dieterhoffman angrily claimed that he'd rather work with the English, and then sent Kurt to grab Dr. Jones. Seigfried was shocked to watch Kurt take the Blueshirt and fatally throw him over the railing to get at Jones. When a brawny Blueshirt went to fight Kurt, Stein took Jones' hand, and then turned and stole the spear tip bundle out of Seigfried's shirt pocket before being pulled upstairs to safety. Being ordered to stop them, Seigfried remained downstairs, away from the brawl between Kurt and the Blueshirt. After Connely clubbed Kurt, Seigfried was astounded when his father shot Connely.
Racing to the cars to chase Jones and Stein, Seigfried and another Nazi rode with Jorge and spied the escapees fleeing from their car in the bog. Jorge drove their car into a deeper pool, which caused the car to sink, and Seigfried tried to get his father to continue the chase rather than rescue them from the roof of their car. However, Dieterhoffmann knew where Jones was going, and stopped to pick up the three stranded men.
Following his father into the New Grange Mound, Seigfried watched as the spear magically reassembled itself, with the piece stolen from him earlier being a fake, but the real piece, hidden in his father's jacket pocket, flying out and joining the assembly held by O'Neal. The spear flew around the room, avoiding Seigfried's grasp, and impaled Kurt. The cave started collapsing, but stopped when O'Neal stood upon an ancient spiral design. After nearly skewering O'Neal, the spear came into the hands of Professor Jones, who held it into the first light of the equinox and witnessed the marvel of the spear tip bleeding. Seigfried and his father, both believers of the spear's magic, also saw the marvel. Unaware that his father was now bleeding profusely and calling for help, Seigfried fell to his knees and began to pray in thanksgiving for seeing the miracle. He continued praying as the mound began to collapse again, his father died, and the others began to escape. While praying that he may pass into eternal life after having been granted his wish to see the spear, Jones dragged him out of the mound to safety.
Lying on the ground outside the collapsed dig site, he babbled as he continued to see a vision of the spear, and expired.
Behind the scenes
The comic Indiana Jones and the Spear of Destiny spells his name as Seigfried, while Indiana Jones: The Ultimate Guide spells his name as Siegfried, which is the more common spelling of the German name.