Each level raises the attack power of the Long Sword by a fair amount. Level zero is the starting level, level one will have a white glow on the Spirit Gauge and the Long Sword itself, level two will have a yellow glow, and level three is red. Spirit Attacks do extra damage, won't bounce off a monster's hide, raise the Spirit Gauge one level upon completing a full combo. This Gauge can be spent on Spirit Attacks. The Gauge decays overtime, however filling it completely locks it for a time, preventing the decay. Every non-Spirit attack from the Long Sword fills the Spirit Gauge a little bit.
On top of its solid base move set, it has a unique Spirit Gauge system.
Hunters are able to roll out of most of the Long Sword's combos, making it a very mobile weapon. Its attacks are relatively fast, deal decent damage, and have good reach.
An elegant weapon, the Long Sword is a well rounded weapon.