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But the other thing is: we’re Vikings. We’re pretty bad at following orders. So consider yourself free again.

–Halfborn after he and the others side with Magnus and his friends in The Sword of Summer.

Halfborn Gunderson was a Norwegian mortal before becoming one of the Einherjar. He died in the Viking invasion of East Anglia, England. He has been at the Hotel Valhalla for 1200 years. He is the on-again-off-again boyfriend of Mallory Keen.


Early Life and Death

Halfborn was born to an unnamed mother and father in an unnamed fishing village (now named Flåm) in Norway. When he was 12 he joined Ivar the Boneless to become a Viking. He told his mother that he wouldn't return until his heroic deeds would be known to the world. He died during the Viking invasion of East Anglia, England. He later on came to Valhalla.

Life in Valhalla

At some point during his time Valhalla, he and TJ at first hated each other, but Mallory managed to make the two befriend one another. Halfborn has visited five of the Nine Worlds, including Midgard, Alfheim, Nidavellir, and Jotunheim. Over his time at Hotel Valhalla, Halfborn has learnt to knit. Halfborn has also learnt 12 different languages (including English and German), and earned a doctorate in Germanic literature over his time in Valhalla.

Magnus Chase and the Gods of Asgard

The Sword of Summer

Halfborn greets Magnus along with TJ, Mallory and X. They explain what life is like at the hotel before battle practice. During battle practice, he is killed. When Magnus flees back to Midgard, he and his hallmates guard them.

He and his hallmates are drafted by Gunilla to arrest Magnus and his friends. They find them as they are about to head to the branches of Yggdrasil, but are stopped by Hearth.

At Lyngvi, they side with Magnus. He fights off the fire giants while Magnus rebounded the Fenris Wolf. After the battle he nearly dies from his wounds, but is saved by Magnus. Back at Valhalla, the eight are brought to the dining hall where X reveals himself to be Odin. He calls the seven of them heroes of Valhalla. He attends the funeral for the fallen Valkyries and begins a relationship with Mallory.

The Hammer of Thor

Halfborn is first seen chasing after his new hallmate with Mallory and T.J. before they run into Magnus. The four investigate their new hallmate's suite and find the mark of Loki on one on the pieces of smashed pottery.

Before battle practice, he was seen adjusting his girlfriend's armor, much to her annoyance. As they are about to start the ravens drop a sack containing Alex Fierro, their new hallmate. They are shocked to see that she is female, as they were told that their new hallmate was male. She tells them not to talk about this and they go to battle practice, where Halfborn is sent flying a dragon's tail.

At dinner, he teases Magnus for staring at Alex and tells him that his father had gender fluid priests. After dinner he, Mallory and T.J. escort her back to floor seventeen.

Two days later, he is watching Samirah al-Abbas and Amir Fadlan argue on a rooftop with Alex, now male. He was acting as a chaperone to Alex, who was acting as a chaperone for Sam and Amir. After the Bifrost is visible, he ops out on meeting with Heimdall as he feels meeting with him once is enough.

At the wedding, he, Mallory, T.J., Blitz and Hearth arrive as backup and help fight the giants. After the battle he celebrates in the feast hall and heads back to his room along with T.J. and Mallory.

The Ship of the Dead

He, Mallory (who he has broken up with) and T.J. are checking their supplies before they leave, just as they are about to leave they are stunned by the colour, neon yellow, of their ship. They pack and board quickly and set sail. He and the other try to steady their boat and avoid plunging into the void. They succeed and wind up in Boston Harbor. They pick up Sam and Alex and Move to pick up Blitz and Hearth when nine women come out of the water and drag their ship down. He is knocked unconscious during the ordeal. He is supported by Mallory and T.J. while Magnus and the children of Loki free Blitz and Hearth. He wakes up just as they are about to eat, only for one of Argir's daughters to recognize Magnus. Aegir eventually calms down and lets them leave if they can escape his daughters. He fights two of the maidens with empty drinking horns. He escapes with the rest of the crew when Njord arrives and Hearth takes out a wall. When they surface he is still woozy from his head injury and vomits. He goes below deck while Magnus, Blitz and Hearth talk with Njord.

He tells Magnus that it is heard for some einherjar to return to the scene of their death, especially if it if years, even centuries, later.

When they arrive at York he, Mallory and Sam watch the ship while Magnus, T.J. and Alex scout out the city. The three defend the ship and his arm winds up in a slow sling. He jokingly lights a match on T.J.'s shrapnel shared but drops it when they realize they are going to Flåm. He heads below deck.

When Magnus, Hearth and Blitz return they land on him. They tell the rest of the crew about their time in Alfheim and they are concerned for Magnus for consuming cursed dragon blood. The next morning they dock in his hometown and he get somewhat emotional. They go in two teams of three to find a train station. He goes with T.J. and Alex while Magnus, Sam and Mallory make the other team. When Baugi attacked the ship Halfborn single-handedly took out the giant, with some help from Alex, when the giant insulted his hometown. He is disappointed that Mallory had not seen his feet, as she was in the walnut shell. They leave Flåm and when night falls he and Magnus talk about his feelings for his hometown. In the morning they arrive in Jotunheim.

They are stranded in the ice close to the border so they decide to walk to shore. When they reach land Skadi invites them in to explain themselves. They bath and have a meal with the giantess. She tells them Loki will launch Naglfar by midday the following day. She also fires an arrow that lands inches from his hand. Skadi hives them permission to spend the night at her fortress. Magnus wakes him up by dowsing him with ice water, twice, before having breakfast and preparing to leave.

He, Blitz, Hearth, T.J., and Mallory go to distract the forces of the dishonourable dead to give Magnus time to flyt Loki. He goes into a rage when a giant insults his hometown. When a ceasefire is called for the flyting he walks over with the name of his hometown painted on his chest in a heart written in giant blood. He is concerned when Magnus is losing but is pleased with his compliments about being a berserker extraordinaire, the glory of Fläm. Magnus reveals to the giant crew how Gunderson conquered kingdoms with Ivar the Boneless, singlehandedly slew Baugi saving his hometown and making his mother proud, steered the Big Banana across the Nine Worlds, how his battle-axe does more damage than most battalions and has done it all shirtless. The crew make their way to the edge of the ship and jump of at Samirah's request. They land on the backs of water horses and swim away just as the harbour is about to freeze over.

They spend three days at sea, during this time he and Mallory become closer. They arrive at Vigridr, where they will die during Ragnarok, and are greeted by the gods. They head over to the feasting tent and hand over Loki. He is given an autographed copy of Odin's new memoir and a bathrobe. They return to Valhalla and during the feast he and Mallory get back together, the pair throw plates at each other and kiss.

9 from the Nine Worlds

So’s Your Face!

He denies Mallory access to his room and the daughter of Frigg throws a slice of pizza at him. Later he finds her and she hugs the berserker.

Well, That Was a Surprise

He lets Alex Fierro into his room to give him shards of broken pottery. He tells Alex, who is male, that he plans on presenting Mallory with a mosaic of their first battle. He asks Alex to keep watch over his room until he gets back from Vanaheim to get dragon scales and he agrees. Halfborn gets to Vanaheim through a sack of potatoes in the feast hall’s refrigerator. When he arrives he thinks he hears a battle and rushes to fight but, much to his dismay, it is a jazz concert. He asks a girl how to get to Freya’s palace and she points him in the right direction.

When he arrives he finds warriors sleeping in hammocks and Freya’s throne empty. He wakes one warrior, Miles, who says that the goddess is out. Miles says the dragons are heavy sleepers and he could easily go up to them and take the scales. Miles takes him and they go off. They find the dragons, but Thor jogs by loudly and wakes them up. They attack and Halfborn, happily, goes beserk and kills all four of them. Meanwhile, others have gathered and are shocked to see him kill the dragons. As he takes their scales he explains that he would have died permanently if he did not kill them and that the dragons will just go to Ginnungagap to be reborn. They then become exited that the dragons will return as babies.

I Play with Fire

He and Mallory are kissing when Alex leaves his room. Later, he and Mallory, along with T.J., Samirah, Blitz and Hearth go to Muspellheim to help Alex fight Surt. However, when they get there they find the ruler of Muspellheim subdued at Alex’s feet.


According to Magnus in The Sword of Summer, Halfborn looks like "Robinson Crusoe on steroids" - with his shirt being a patchwork of animal pelts, his hide pants in tatters and his beard being wild even by Viking standards.


Halfborn is shown to be a loyal warrior, as he his merciless on the battlefield, and a caring friend, he goes to great lengths to keep his friends safe.


  • Fighting Skills: Halfborn is an extremely skilled warrior with 1200 years of experience.
  • Pain Tolerance: As a berserker, Halfborn has an extremely high pain tolerance, being oblivious to pain. He is said to fight until “he is literally hacked to pieces“.
  • Multilingualism: Halfborn can speak twelve languages (including English, Old Norse, and German). He has obtained a doctorate in German literature during his time in Valhalla.
  • Knitting Skills:During his time in Valhalla, Halfborn has learned how to knit.

  • Einherjar Immortality: While within Hotel Valhalla, Halfborn, like any of the einherjar, cannot die, and will simply keep resurrecting from mortal wounds.
  • Enhanced Strength: After gaining a new einherji body, Halborn gained a degree of superhuman strength.
    • Enhanced Agility: after gaining an einherjar body, Halfborn, has become much more agile.

  • Relationships

    Love Interest

    Mallory Keen

    Mallory and Halfborn have known each other since the early 1970s, when Mallory died disarming a car bomb. However, the two did not start dating until fifty years later. He would compliment her and she would insult him in return. However, the two broke up in The Ship of the Dead and would spend the trip arguing. However, by the end of the quest, the two have reconciled and are back together.



    The last time Halfborn saw his mother when before he went with Ivar the boneless to raid and pillage and promised never to return until he was a successful explorer. However, he died during a fight in England and never saw her again. Hundreds of years later he states that he misses her.


    Magnus Chase

    Halfborn was warm to the son of Frey from the start. He tells him not to close himself off and to interact with others. As time went on the two became close.

    Thomas Jefferson Jr.

    For the first hundred and ten or so years of the son of Tyr’s time in Valhalla, the two were bitter rivals. It was not until the arrival of Mallory Keen that the two became friends.

    Samirah al-Abbas

    The Berserker has a deep respect for the Valkyrie, this respect grew after he saw her tame a water horse.

    Alex Fierro

    While the berserker was cautious of the child of Loki at first, he quickly came to befriend Alex.


    • Halfborn has a fondness for Native Americans, whom he refers to as Skraelings (vicious fighters).
    • It is possible that Halfborn is a true Viking as his death put him around the time of the original Vikings.
    • He is the only person on floor 19 who's parentage is unknown, as of 9 from the Nine Worlds.
    • He is in a relationship with Mallory Keen.
    • Due to the norse naming tradition of an individual’s last name being there father’s first name with suffix of “son” for sons and “ditter” for daughters, it can be assumed his father’s name is Gunder.
    • Halfborn is the fourth human to have a point of view after Dr. Howard Claymore, Randolph Chase, and Amir Fadlan.
    Magnus Chase and the Gods of Asgard
    Core Series: The Sword of Summer | The Hammer of Thor | The Ship of the Dead
    Main Characters: Magnus Chase | Alex Fierro | Blitzen | Halfborn Gunderson | Hearthstone | Loki | Mallory Keen | Samirah al-Abbas | Sumarbrander | Thomas Jefferson Jr.
    Secondary Characters: Randolph Chase | Gunilla | Natalie Chase | Amir Fadlan | Alderman
    Minor Characters: Annabeth Chase | Frederick Chase | Helgi | Hunding | Vala | Junior | Lars Alhstrom | Stanley | Inge | Percy Jackson | Stan | Alviss | Miles | Wildflower | Sunspot | John Henry
    Norse Gods: Freya | Thor | Balder | Ullr | Frey | Odin | Heimdall | Vidar | Sif | Frigg | Tyr
    Minor Gods: Skírnir | Mimir | Ran | Hod | Hel | Sigyn | Aegir | Nine Billow Maidens | Njord | Kvasir | Holler | Forseti | Glum | Lofn | Sól | Idunn
    Jotnar: Surt | Gerd | Norns | Utgard-Loki | Harald | Ymir | Geirrod | Gjalp | Greip | Thrym | Thrynga | Tiny | Little Billy | Hrungnir | Red | Tattoo | Gunlod | Suttung | Baugi | Skadi | Hrym | Eggther | Norns
    Monsters: Jormungand | Ratatosk | Vedrfolnir | Nidhogg | Fenris Wolf | Lindworm | Wight | Brunnmigi | Siersgrunnr | Garm
    Magical Creatures: Dwarf | Elf | Sleipnir | Stanley | Marvin | Otis | Hulder | Nøkks | Vatnavaettir | Nisser | Troll | Raven | Hugin and Munin
    Related Content: Rick Riordan | Hotel Valhalla Guide to the Norse Worlds | 9 from the Nine Worlds