At the entrance to Thrymheim, Yui explained that the quest they were given was created by the Cardinal System's «Automatic Quest Generation Function» and that if they did not succeed in their quest, a final war event, Ragnarok, would be triggered, resulting in the destruction of Alfheim and the World Tree. The group was in disbelief, until Yui reminded them that Cardinal's final task was to destroy Aincrad in Sword Art Online in the same manner. With no other option and time running out, the group quickly proceeded to finish the quest.
At the end of the second floor of Thrymheim, the group encountered two minotaurs, one of which had high resistance for magical attacks, the other for physical attacks and the two would change places to heal after having suffered too much damage. As the party did not have any mages with offensive spells, they relied on Sword Skills that could deal elemental damage in addition to physical damage, but left the player rigid for a few seconds after the skill ended. With Kirito revealing his new technique of using consecutive Sword Skills with each of his swords to avoid the period of rigidity, they were able to defeat the two minotaurs.
After defeating the boss guarding the entrance to the lowest floor of the castle, the fairies encountered a Non-Player Character (NPC) woman trapped in an ice cage along the way. However, this woman had a Hit Point (HP) gauge, leading Kirito to believe that they group may have to fight her if they released her. Although the group insisted that it was a trap and planned to avoid her, Klein ignored their advice and freed the woman, who was revealed to be Freyja. Instead of running away, Freyja asked to join the group to reclaim her family's treasure that was stolen by Thrym and Kirito reluctantly agreed to the request. After preparing for the final battle by planning their strategy and recharging their buffs, the group entered the throne room where they met the king of the frost giants, Thrym.
- Centipede-like giant
- «Howling Octave» - Kirito
- «Savage Fulcrum» - Kirito
- «Horizontal Square» - Kirito
- «Vorpal Strike» - Kirito
- Adapted from Volume 8, Calibur, Part 3-4
- Kirito's use of «Vertical Square» against the minotaur was changed to the use of «Horizontal Square».
- Instances of puzzles that had to be solved to proceed through Thrymheim were all omitted.
- Although Asuna chanted the spell for a strength buff, the animation showed that she had cast a cold resistance spell.
- Savage Fulcrum was supposed to consist of a horizontal slash, an upward vertical slash followed by a downward vertical slash. However, the last slash in the combo was omitted in the anime.