In Genealogy of the Holy War, the Helswath grants its wielder bonuses of +20 Defence and +10 Resistance. This axe may only be wielded by users possessing major Neir holy blood, with the only characters fulfilling this criteria being Langobalt, Burian and Danan. The axe is always wielded by an enemy unit and is unobtainable.
The Helswath makes its first appearance in Chapter 5 of Genealogy of the Holy War, where it is wielded by Langobalt, who falls to Sigurd's army in the attempt to defend Lubeck Castle.
The Helswath later appears in the Final Chapter, where it is observed to have been inherited by Burian, the oldest grandson of Langobalt. Leading the charge against Seliph's army after Edda Castle is conquered with the Grauen Ritter Brigade, Burian eventually falls in the attempt. The whereabouts of the Helswath following Burian's death is unknown.