Siggy was the enigmatic widow of Earl Haraldson.
During her husband's reign, Siggy was much-admired and performed her duties impeccably. Siggy easily gained the trust of others, though she was not as trustworthy as people thought. Siggy's loyalties constantly shifted, lying where they would benefit her. She may have played the devoted wife, but she was above all a ruthless survivor. Siggy was still madly in love with her husband and missed him very much.
Siggy is the wife of Earl Haraldson and mother of a daughter, Thyri, and their two late sons. She is mostly at her husband's side, they form a team, Siggy helps her loving husband. She is displeased with Earl Haraldson's decision to marry their daughter to a fellow Earl, Bjarni, from Svealand. When Ragnar and Haraldson fight each other in personal combat, she roots for her husband, but when Ragnar defeats and kills him, she tries to not cry so she quickly defects to his side to stay safe and protect her daughter, kills the husband of her daughter and steers the citizens of Kattegat to hail their new Earl. At the funeral of Earl Haraldson, she asks Earl Ragnar permission to light the pyre, but he mockingly hands the torch to a man. It seems like she wants to stay in the boat and burn with her husband. Later, she and her daughter pack some of their treasures to leave, when Rollo enters. Startled, Siggy assumes he has come to kill them by orders from Ragnar, but he says Ragnar holds no grudges against them and they don't have to leave as he will vouch for them. Rollo forces Siggy to marry him if she wants her daughter and herself to be protected.
When Ragnar goes on another raid to England, Siggy enters the Earl's home to ask Lagertha permission to be their servant. The new Earl's wife accepts, saying she would have done the same if Haraldson had defeated Ragnar, despite protests by Bjorn. She acts as a servant to the Earl's family and lover of Rollo. Siggy comforts Lagertha when she lost her and Ragnar's unborn son in a miscarriage. She also travels along with Ragnar's family, Rollo and her daughter Thyri to Uppsala for the ritual sacrifice.
When Ragnar and Rollo have joined with King Horik to help end a dispute with Jarl Borg from Gotland, Kattegat is struck by a plague. Siggy, Thyri, Gyda and Athelstan are among the people who get sick. Although Siggy recovers, she is heartbroken when she finds out her daughter has perished, along with Ragnar's and Lagertha's daughter Gyda.
Four years have passed since Rollo fought against his brother, Ragnar, and barely escaped execution. At the news that Ragnar is once again seeking to raid England, Siggy seeks out Rollo, who's asleep in the street. She gives him the ultimatum of either asking to join the raid or to "have a blade shoved into his ribs.” Rollo visit his brother, who welcomes him back as kin, but refuses to let him join the raid. Siggy, meanwhile, pays a visit to King Horik to relay information about Ragnar. "It is always a strength to know the weakness of your friends," she tells him, before they sleep together.
While the boats set sail, Aslaug invites Siggy to join her in her chambers. Aslaug offers her hand in friendship, though she acknowledges that Siggy must also yearn for the same power she now wields (and what Siggy once had). Bitter at being uninvited from the raid, Jarl Borg sets his sights on Kattegat. With his ships on the horizon, Siggy plans to fight back; Rollo tells her she needs to take Aslaug and her sons to safety. Realizing the battle is lost, and wanting to ensure Ragnar's family remains safe, Rollo leaves Kattegat to join Aslaug and Siggy. Though they are safe, Aslaug complains tirelessly at how dirty and uncomfortable her new home in the mountains is. Siggy retorts that she should be happy they are all alive.
Meanwhile, in England, Ragnar receives word that Kattegat has been taken over by Jarl Borg. He immediately returns home and is pleased to find his wife and sons uninjured. Ragnar wastes no time to plot revenge; though he is surprised to see that Lagertha and Bjorn have come to his aid with reinforcements. Together, they manage to beat Jarl Borg back and retake Kattegat.
Several days later, Siggy meets with a seer and reveals she is bitter and angry that Ragnar killed her husband. "Everything I was had been stripped away from me", she tells the seer. She is unable to forgive Ragnar, but the seer says Ragnar could have easily have killed her as well. Siggy refuses to be grateful to her husband's murderer and asks if the gods will ever smile on her again. "The gods always smile on brave women", he says.
A dinner party is held upon the return of King Horik and the remaining men from England. He tells Ragnar that they were ambushed and barely made it out alive. In order to go back, however, King Horik believes they need the help of Jarl Borg – Rollo is chosen to go.
The next day, Rollo leaves to speak with Jarl Borg; he and Siggy share a fond farewell. After the dinner party, Siggy meets with King Horik, who has also invited his son to witness the "game" they play. King Horik asks her why she invites him to her bed to relay information about Ragnar. Siggy replies that everything she does, she does for Rollo. The King doesn't seem convinced. He tells Siggy that he wants her to make his son Erlendur a man. Siggy toys with the idea, and eventually gives in to King Horik's wishes.
Ragnar and Lagertha's fleets depart for Wessex, this time bringing settlers as well as warriors. In Kattegat, Siggy, Helga and Aslaug find out that they are all having the same unusual dream about a stranger, a man with no face. There's snow on the ground, footsteps therein. The stranger’s arms outstretched: Flaming snow in one hand, his other hand covered in blood. Behind him, drops of blood smoke in the ground. The women do not seem very concerned about the dream, however, until the 'wandering' shows up.
Harbard the Wanderer walks into Kattegat, one hand bleeding. He is invited to stay, nonetheless, though Siggy is suspicious, as per the norm. He tells the women – Siggy, Aslaug and Helga – that he tells stories for a living. Harbard later sings for his supper, telling a great and fantastic story about himself, which Siggy does not believe. Helga realizes he must be Thor and Harbard plays along, agreeing to the notion. Conversation is interrupted by Aslaug's youngest son, the crippled child Ivar, who starts to cry. Harbard goes to him, and quietly speaks to the little boy, putting him to sleep. Siggy is even more suspicious, though a little relieved to have some help. Harbard proves able to calm the shrieking child at other times as well, prompting Siggy to ask if he is a god.
Siggy goes to see the Seer, telling him about the strange wanderer, the dreams that preceded him, the premonitions of disaster. He has seen nothing. But Siggy has – she tells the Seer about the dream, and saw that no one could help them. The Seer agrees – no one can help them.
Meanwhile, Aslaug and Harbard have grown closer. Siggy begs her to take some responsibility; there are people to be seen, decisions to be made. Aslaug is weary, she knows what Ragnar is doing abroad – she was once herself the desirable princess, though now Ragnar seems less than interested in her. Siggy takes over her responsibilities, however, which for now include watching over Aslaug's sons.
The boys race off onto the frozen lake, causing the ice to crack. The boys fall into the water and Siggy immediately jumps in after them. Harbard also arrives to pull the boys from Siggy's arms. Siggy, however, does not fight anymore. A vision of her deceased daughter, Thyri, prompts her to let go. She drifts into the icy water. She rejoins her husband in Valhalla.
- Thyri – the only surviving child of Siggy and Earl Haraldson, she is a quiet girl in her early-teens who is an unfortunate pawn in her father's plans. She is married to the much older Earl Bjarni, who is cruel to her. Her life is cut short by a plague that hits Kattegat.
- Sons – two sons who were brutally murdered and disfigured. Their father vows revenge on the person or persons who killed them.
|Season one appearances|
|Rites of Passage||Wrath of the Northmen||Dispossessed|
|Trial||Raid||Burial of the Dead|
|A King's Ransom||Sacrifice||All Change|
|Season two appearances|
|Brother's War||Invasion||Treachery||Eye For an Eye||Answers in Blood|
|Unforgiven||Blood Eagle||Boneless||The Choice||The Lord's Prayer|
|Season three appearances|
|Mercenary||The Wanderer||Warrior's Fate||Scarred||The Usurper|
|Born Again||Paris||To the Gates!||Breaking Point||The Dead|