Role in Eragon
Prior to the infiltration of the castle in Teirm, Brom told Jeod that his rapier would be useless against flamberges or broadswords. Jeod countered that by saying that a rapier was far quicker than a broadsword and no guards carried a flamberge. Eragon thought the rapier was elegant and somewhat complemented Jeod.
Real World Connections
The term flamberge literally means "flame blade or fire blade": a flamberge is a special form of rapier that is manufactured with an undulating blade. Parrying such blades requires an opponent to possess great skill, stamina and agility, because when an opponent's blade came into contact with a flamberge, the contact resulted in the flamberge emitting vibrations that were transmitted to the opponent's blade. The vibrations slowed the ability of the opponent to counter an attack because, with each successive attack the amount of resistance caused by the contact with the undulating blade increased slowing the force and velocity of the opponent's weapon.
The term flamberge has often been misapplied to larger swords related to Hand-and-a-half sword or two handed swords that are more properly called either flambards or flammards. Such swords can be commonly seen on display in medieval castles throughout Europe that are open to visitors, often with the commentary that they were used for ceremonial purposes, mainly knighting ceremonies. This is partially true, as in certain times and places wave-bladed two-handed swords were used for fighting as well. Still, these swords were among the largest and heaviest of their kind, making their use in battle somewhat impractical for the average foot soldier. However, for a stronger soldier they are a good option when strength is required. However, because of their weight and strength they would be good when used by a soldier of another race besides Humans such as Urgals. On the other hand, they looked impressive, making their use for ceremonial or representative purposes far from unlikely.