Longsword is a main handed weapon for fighters, valkyrie, lord, samurais and ninjas -- which are all specializing in using swords. It is a main handed weapon, in which the sword uses one hand, while a sub handed sword or a shield is on the other. Attacking is once per turn.
The character has to be in the first three slots to use it and attacks the front row of enemies, due to its short range of attack.. The chance of landing a hit has no increase nor decrease, and it doesn't have any noticeable increase nor decrease in any elements, spells and status ailments. It has gender and alignment restrictions. Everyone but fairies can use it.
Ghost enemies are immune over being hit. You can buy it at Jadgebol Shoppe, or get it from treasure chests.