Siegfried Sigmundson, real name Geralt, is a playable character in Blackmoon Prophecy.
During his journey, Siegfried comes to Lenadia Kingdom in search of Excalibur, but his journey is halted on his way to Castle plains where the bridge leading inland is blocked. He then heads to Cornelia where he waits for the blockade to be lifted. Few days later Siegfried is approached by a dragoon while he is siting at the town pub. Initially he loaths the dragoon and attempts to get rid of him, but after the two share their stories, Siegfried offers to join Vahn on his journey, hoping that in his travels he will find Excalibur, the sword he is looking for. He then challenges him to a one-on-one duel as a form of test and the dragoon bests him, resulting in the swordsman joining his group. The man introduces himself to the swordsman as "Vahn", irritated by him constatly calling the other "dragoon". The group then decides to spend a night at Cornelia, waiting for the blockade to lift off. Vera is thinking about Ivalice, when Ami unexpectedly joins her. Vera reveals to her that she must have a sleeping problem, but also a lot on her mind, especially since rejoining Vaan, and Ami takes it for a forming deep bond between the two. Vera denies it and asks Ami about her carefree behavior that somewhat contradicts her age, all while briefly being spied by Nobumasa. Ami says that behavior does not bother her and she can be serious, and she offers Vera to demonstrate it. Vera refuses and advises them to go get some rest or Vahn will have problems waking them up and the two retire to the inn. The next day the group arrives at Lenadia Castle where King Gorn informs them that the reason why the bridge was out yesterday was because of a diplomatic group from Ivalice. Vahn informs the King about Malacore and his plan, and the King allows them to check up on the Crystal of Wind while he consults with his strategists. Vahn and his party arrives at the Crystal Chamber in Wind Shrine where Malacore is already attending to the Crystal. The being orders the Necromancer to fight the dragoon and his party, but by defeating it the party is too slow to stop Malacore who has absorbed the Crystal's power. Malacore then challenges the party to a battle, intending to demonstrate his newly acquired power, but a voice interrupts him. Malacore recognizes the voice and identifies it as Darius, who has slept within Malacore. The fallen dragoon then taps into the Crystal power absorbed by Malacore and frees himself from the ties to Malacore and materializes before the entity is able to neutralize his consciousness. Darius then attacks Malacore with the power he attained from his ties to him and the being escapes, shortly after declaring its next target: the Crystal of Earth. Vahn decides to quickly go to Lindblum Kingdom and wonders if Darius will join him if he is not intending to return to Branch. Now the dark knight then says thay he wishes for nothing else and that he wants to pay back to Malacore for what he did to him. Just as the party leaves the Wind Shrine, Braak appears in the back noting how fruitful spying on Vahn and Vera has turned out. When the party returns, Lenadia Castle is under Ivalice attack and the group rushes to the throne room. In the throne room, Vahn comes across Braak, Deckar, and Eva and the blonde general reveals that Ivalice has suspected of something going on in Branch, hence his appearance there. Braak reveals that the Emperor wants to rule the world, seeing how Crystal power is powerful, and in order to achieve it he plans on conquering other lands. Appaled by hearing the generals' words, Vahn and his party fight and defeat them. Before teleporting away, Braak promises King Gorn that "this is only the beginning". The group retreats with the King to the conference room where they relay him the fate of the Crystal of Wind. During their conversation, Vahn reveals to King Gorn that apart of Malacore and Ivalice Empire, there are also Archareons who pose threat to them. The King says that the group shouldn't concern themselves with Ivalice for the time being as he will involve Lenadia in this matter, but also pursue alliance with other kingdoms. Darius then suggests going to Lindblum to to prevent Malacore from absorbing the Crystal of Earth. Back in Cornelia, Vahn enlists Cid to help him and his group travel to Lindblum.
After arriving in Lindblum, the party goes through the Cave of Dreams. Deep within the cave, most of the party suddenly falls asleep, with the exception of Ami and Nobumasa. In the dreams, Vahn appears in his hometown of Valla. He talks with his mother Elise who informs him that a dinner will be soon and Vahn decides to look around town. When he returns home, he says he has helped a girl find her doll and when he starts to inquire her about his father, Elise refuses to speak about it and the dragoon steps out of the house. When he enters the Elder's house and asks him about his father, the Elder assumes a monstrous form and multiplies across all over the house, promising him to tell Vahn provided he will stay forever in the town. Another dream takes Oalston back to Trei, in a setting where Malacore was defeated. Everyone is hateful towards Oalston and when he inquires the doctor about it he learns that he has murdered Maria. The guard then arrive and with the help of Doctor Cunnings they strip him of his power and imprison in his own house. Next dream takes Darius back to Branch, also after Malacore's defeat, where he returns to former glory and is assigned the role of general. Lord Adder orders him then to go to Meksicburg and slaughter anyone who does not show any respect for the dragoons since the townsfolk does so on regular basis. Darius is surprised by Lord Adder's course of actions, but he intends to carry the order out after the Lord's harsh words. From the other dragoon Darius learns that Lord Adder plans to launch an assault on Ivalice, and the dark knight decides to look for Vahn and Hans hoping they would talk some sense into their leader. He finds them in the dungeon where they inform Vera of her incoming execution and Darius decides to save her, only to be attacked by Vera. Hans and Vahn then turn into humanoid dragons that intend to put him to sleep. Elina's dream world is set in Mystic Mysidia's Elder's house where she writes a letter to her mom about how everyone praises her progress in styding white magic, however she feels insecure about her abilities. In the town she comes across ghosts disgusted by her. Back in the Elder's house she comes across Vartz who mocks her and reveals that because of her lack of abilities she couldn't save anyone and now is alone. Another dream world takes place in Albrook where Vera is hunted down by Ivalice soldiers, who upon seeing the situation in town decides to go to Branch and see Vahn. However as she is about to leave the town, she is strangely teleported to its entrance once again and falls asleep. Siegfried's dream takes place in a forest where he is searching for the Excalibur. Deep within the forest he comes across an old fisherman who reveals that the "Excalibur" is just a fishing hook and when Siegfried faints, the old man is joyful with the other man's failure. Back in the Cave of Dreams, Ami tries to persuade a creature to stop its doings, but Nobumasa urges her to take action, fearing for their comrades. The two defeat the demon and their friends wake up. Hearing from Nobumasa about the creature, Vahn urges the party to quickly leave the place, fearing that more monsters of that kind might be still in the Cave.
Arriving in Lantz, the group learns from the town Elder that a rebellion has grown in Lindblum, mainly fueled by the unrest caused by the Regent's priority on increasing the Kingdom's economical value. The rebels frequently destroy bridges that connect Lantz to western Kingdom and Vahn and his party volunteer to talk to the rebels and convince them to stop their actions. The party then departs east, on a newly rebuilt bridge to find the rebel base. While resting at the inn, Vera invites Vahn to a stroll across the riverbank and the dragoon takes her upon the offer. During their walk, Vahn expresses his doubts about being able to save the Crystal of Earth before Malacore absorbs it and Vera calms him by saying that as they travel the world they are also enlisting help of kingdoms' leaders and that Malacore has no way to win against that meny people. Suddenly a group of rebels appears and the two quickly dispatch them before they destroy it. After they return to Lantz to speak with the Elder, they comes across a group of rebels in his house and dispatch them. They then go after the Elder to rebels' hideout. Vahn successfully rescues the Elder in Rebel Hideout and they return to Lantz. With the Elder back in town, the western bridge leading to western Lindblum is rebuilt and the party continues on their journey. Coming to Surgate Waystation, Vahn tries to enter the lone building hoping to buy some supplies, but seeing how it is closed he decides to do it in the next town. As he is about to leave the place, several rebels come in an overwhelming number. Not wanting to fight a lost battle, Vahn notices a chocobo pen and escapes on one of the birds. As they are making their way through the rebels, Vahn is hit by a lightning spell and he and chocobo collapse. When he get up, he encounters Hans. The party fights the rogue dragoon and defeats him, but he teleports away. Some time later the party arrives at the Mage Academy and upon Oalston's suggestion they decide to stay there for a bit, while he and Elina explore and possibly learn something new. Oalston comes across Anders, who informs his fellow mage that non-elemental magic exists, surprising Oalston. He offers to teach him Comet after passing three tests administered by other people living in the Academy, first being Brawn, second Walter, and the third by Balthier. Overcoming their trials, Oalston returns to Anders who challenges him to complete all three trials in a single battle. Winning the battle, Oalston learns Comet from a book. Meanwhile searching for help, Elina comes across Lyon who directs her to Sabino. He challenges her to a trial in order to get a new spell by testing her ability to switch between offensive and defensive tactics. Winning the battle earns Elina right to learn Prayer.
Arriving at Lindblum Castle, Vahn speak with Regent Gran and warns him about the danger that awaits the Crystal of Earth. The Regent says that he knows about it and is currently working hard trying to reclaim it. Asking if it was Malacore's doing, Regent Gran says that this is the first time he hears about such entity and says that the Fen of the Underworld have stole the Crystal. He reveals that two nights ago the Fen has come to Mt. Koltz where the shrine to the Crystal is located, breached to its Chamber, and after escaping to the Underworld with it they sealed the way with a powerful magic barrier. Hearing about difficulties that Lindblum mages have with disabling the barrier, Oalston, Elina, and Vera volunteer to help them and are escorted by the soldiers to aid the mages. With the three gone, Regent Gran asks Vahn and his remaining allies to help him stop the rebellion led by Baram. Vahn agrees and is tasked with liberating the town of Dawnmarch from rebels. Regent Gran arranges a chocobo for him, allowing the group free travel across the continent.
After Zeul's defeat, Siegfried disappeared. Despite finding Excalibur, he is not satisfied and feels empty after leaving his love Davon in search of the legendary sword. After learning that she died of what appeared to be broken heart, Siegfried plunged himself off of the top of Mt. Houzell taking his own life to reunite with his love.
Ninety one years later, a young man by the name of Silas Hedgeley finds his armor and decides to train as a swordsman wielding the old sword he found within it.
- Main article: Sword Art (Blackmoon Prophecy)