In Genealogy of the Holy War, the Gáe Bolg grants its wielder bonuses of +10 Strength, +10 Skill and +10 Defense. This lance may only be wielded by users possessing major Noba holy blood, the only characters with this requirement being Quan and his daughter Altena.
The Gáe Bolg is said to be have a curse that visits tragedy upon its owner. The story of this curse began with the brother and sister CrusadersNoba and Dain, who shared a close sibling relationship. This intimacy caused them to jointly rule the Thracian Peninsula as one country, comprising both the Manster District and Thracian Peninsula.
At some point, Noba wed a knight who was a good friend of her brother's, and the two lived happily for a good while. However, Noba's husband and Dain later got into an argument, one that led to them dueling each other. In an attempt to break up the fight, Noba accidentally impaled her husband with the Gáe Bolg. This was quickly followed by Noba committing suicide out of both grief and guilt, alongside Dain dying under mysterious circumstances. A series of unfortunate events occurring within the Leonster royal family then occured, which eventually caused Thracia to split into two distinct northern and southern districts.
After these events, it became known that the Gungnir and the Gáe Bolg were intertwined, and that the Gáe Bolg is the lance that controls both love and sorrow, promising to tear asunder any couple whose hands it falls into. For this reason, Ethlyn is initially hesitant to give Quan the lance in Chapter 3 of Genealogy of the Holy War, as she believes that it will end up in their happiness being ruined by Quan's death. Both the Yied Massacre, where Quan (who possessed the Gáe Bolg) and Ethlyn are killed by Travant (who possessed the Gungnir), and the conflict that separates the step-siblings Areone and Altena in Chapter 9 are said to be due to the Curse of the Gáe Bolg. The curse may have been ended by the step-siblings' reunion in Grannvale.
The Gáe Bolg's in-game design appears to differ from its official artwork depiction. While the lance's official artwork shows it with a yellow swirl surrounding a red jewel in the middle of the lance, its in-game design lacks this detail.