Storm Brand

The Storm Brand is a Long Sword-class weapon Artifact available in Golden Sun: The Lost Age. It is found in a treasure chest in the first screen at the bottom of the massive Air's Rock dungeon. Being a Long Sword-class weapon, the Storm Brand can be equipped on warrior-style Adepts, namely Felix and Piers, and also Isaac and Garet when they join up late in The Lost Age. Its buy value is 3900 coins and its sell value is 2925 coins.

The Storm Brand increases the wielder's base Attack rating by 60 points. Its Unleash effect is Hurricane, with the standard base activation rate of 35%, which is a physical attack with an additional 21 points of damage added, and then the resulting damage is either increased or decreased based on how the user's Mercury power measures against the target's Mercury resistance. The Unleash may also decrease the target's total Attack rating by 25% (the maximum amount any character or enemy in the game can have its Attack rating decreased or increased is up to 50% from the norm, so this side effect can successfully occur twice profitably). Visually, Hurricane resembles a torrent of rain drops hitting the target before the holder of the sword attacks them physically.

Analysis
The Storm Brand is a textbook example of a weapon artifact in The Lost Age that is found in a chest in one of the game's big dungeon-style locations, and when it can first be found it is noticeably strong, certainly stronger than any weapon Artifact that you can buy from vendors at the time. It is easily the strongest weapon you can find yet for Felix during your first visit to Osenia and is useful to use in the Briggs boss battle, in spite of the fact Felix is a Venus Adept and the weapon's Unleash effect is Mercury-based. When travelling into lower Gondowan sometime afterwards, the Storm Brand will be outclassed by the Disk Axe you can find in Kibombo Mountains, but it is advisable to keep it in your inventory for when the Mercury Adept warrior Piers joins your party shortly afterward. He will be holding a Battle Mace, but the Storm Brand is an instant perfect fit for him because it has even more Attack and Piers' Mercury power (as well as the fact he can potentially have four Mercury Djinn set onto him as soon as he joins) will make the Hurricane unleash all the more damaging. The Storm Brand can easily last a while, and can be reliably replaced by the Mist Sabre found in Aqua Rock later on (or a Comet Mace if you manage to forge it from Stardust at the blacksmith in Yallam).