Excalibur

An Excalibur is an Artifact Long Sword-class weapon available in Golden Sun: The Lost Age and Golden Sun: Dark Dawn. It is forged from an Orihalcon, and it has one of the highest base attack ratings of any weapon in the series and one of the most powerful Unleashes as well.

Basic description by game
In The Lost Age, Excalibur increases its wielder's base Attack by 180 points, second only to the unique Sol Blade and the cursed Darksword. The blacksmith in Yallam, Sunshine, forges Excalibur at random from Orihalcon at a rate of 5%. The initial price is 29200 coins, and it can be sold for 21900 coins and bought back for the same. As a Long Sword, it can be wielded by Felix, Piers, Isaac, and Garet.

Its Unleash effect, Legend, deals a Jupiter-aligned attack equal to the user's normal physical attack with 73 damage points added to the  results, and there is a 60% chance that it will multiply the resultant damage by 3. Therefore, it can be said that this Unleash has an average damage multiplier of 2.2. Visually, Legend resembles a purple light hologram of a symbol forming above the enemy party, generating either one or three holographic swords that drive into the target, depending on whether the damage was tripled by the effect.

In Dark Dawn, Excalibur is obtained in much the same way—give Obaba an Orihalcon and hope she forges this. Unlike Sunshine, Obaba will give it to the party for free. As a Long Sword, it can be wielded by Matthew and Tyrell. With Dark Dawn's different Unleash mechanics, Legend is now the fourth and final Unleash that the wielder may gain the ability to randomly choose from whenever he unleashes. Its first Unleash is Critical Move, which is simply a physical attack with the resultant damage multiplied by 1.4. Its second Unleash is Rolling Attack, a Jupiter-aligned attack equal to the user's normal physical attack with the result multiplied by 1.1, and hits each adjacent foe. Its third Unleash is Sky Diver, a Jupiter-aligned attack equal to the user's normal  physical attack with 66 added damage, and the chance to Stun the target.

The Lost Age
In The Lost Age, Excalibur is often identified as one of the game's ultimate weapons, by virtue of its being the closest weapon to the Sol Blade in power and usability. The Sol Blade has 20 more base Attack, and its Megiddo Unleash automatically triples all damage dealt; it's an ideal choice for Isaac or Felix. Nevertheless, only one can be obtained, and Excalibur is still arguably the best weapon for the other three Long Sword wielding warriors. It has two points of Attack more than the Tisiphone Edge, but the deciding factor between the two weapons is really the elemental power of each: Tisphone Edge's Venus power or Excalibur's Jupiter power. The Attack difference is negligible. Unlike with the Sol Blade, it's possible to get multiple copies of Excalibur, and because of their power, three Excaliburs are a great asset. They're perfect weapons for the final battle and for fighting any of the optional bosses—Valukar, Sentinel, Star Magician, and Dullahan.

Excalibur's Legend Unleash is generally a weaker, more randomized form of Sol Blade's Megiddo; but it can triple its damage 60% of the time (including the 73 extra Jupiter damage), giving it 219 bonus damage. As a result, it is weaker on average, but at full power, it is essentially a better result than Megiddo on the same target. Like with the Sol Blade, Excalibur's usefulness can be enormously improved by its user wearing lots of gear that augments Unleash rates, like the Valkyrie Mail or Mythril Clothes, the Mythril Helm or Warrior's Helm, the Riot Gloves or Aegis Shield, and most certainly, the Hyper Boots.

That Legend's elemental affinity is Jupiter is a minor downside because there are no Long Sword-wielding Jupiter Adepts whose Jupiter power ratings can work in tandem with the Unleash. The ideal user of Excalibur is an Adept in the Master class, which is just like the excellent Chaos Lord class in having the highest attack rating in the game, but it also has five Jupiter Djinn Set to grant the wielder 25 additional Jupiter power. When it comes to equipment that can also increase the warrior Adept's Jupiter power, the only possibilities that exist are the Aerial Gloves and Planet Armor, and one would not want to wear these in place of the gloves and armor that increase Unleash rate, like the Mythril Clothes and Aegis Shield noted above.

Dark Dawn
In Dark Dawn, Matthew and Tyrell are the only Long Sword users, and since Matthew would be holding the game's best weapon, the Sol Blade (which only he can equip anyway), the only character to use Excalibur is Tyrell. As a result, only one Excalibur at most can be useful for an end-game party. Like before, the Master and Chaos Lord classes are the best classes for Matthew or Tyrell to be using Excalibur with because of the top-notch attack ratings they provide and the Master class's Jupiter power boost.

While still useful, Excalibur's power has abated substantially from The Lost Age thanks to the new Unleash system, which adds weaker Unleashes that the game randomly chooses from each time the user makes an Unleash with the weapon. The other "ultimate" weapons weaken in power for the same reasons, but Excalibur is particularly downgraded in usability because it now has three other unleashes that are all weaker than Legend. The first Unleash that the wielder may learn to trigger, Critical Move, is a physical attack with a damage multiplier of x1.4. To put this in perspective, the Wooden Stick has a multiplier of x1.5 when it Unleashes (though to be fair, the comparative weakness of said weapons and others that use that unleash would result in a smaller overall damage bonus).

The second Unleash, Rolling Attack, is a Jupiter-aligned attack equal to the user's physical attack with a x1.1 multiplier, and it hits each adjacent foe, up to three at once. This is somewhat useful in random battles, but it's weak even for a multi-target attack, compared to the Darksword's Spiral Assault Unleash. Excalibur's third Unleash, Sky Diver, is another Jupiter-aligned Unleash, and while it adds 66 damage and may Stun the target, it has no damage multiplier. Since all three of the Excalibur's elementally-aligned Unleashes are aligned with Jupiter, the increased Jupiter Power of the Master class does become a bonus that's all the more relevant. But unfortunately, with Legend now being one of four randomly chosen Unleashes, on top of its only having the chance to trigger its damage-tripling effect when it is Unleashed, scoring that enormous burst of damage with an Excalibur unleash is now rather uncommon.

As a result, Excalibur can no longer be considered the penultimate Long Sword after the Sol Blade, and it is now completely outclassed by the Levatine as a weapon for Tyrell. While the Levatine's first Unleash is the same wimpy Critical Move, it lacks a fourth Unleash, so each better Unleash happens more frequently. On average, Excalibur has a damage multiplier of about x1.4, whereas Levatine has x1.6. A damage-tripled Legend Unleash is still potentially the most powerful Unleash in the game, but it triggers so uncommonly that it might be a waste on most enemies.

Overall, Excalibur has fallen far from its Lost Age title as an ultimate weapon. It's still good for Tyrell if the player manages to forge it from an Orihalcon without getting a Levatine from a Mythril Silver, but this scenario is unlikely because the Levatine has a higher chance of being forged, and Mythril Silver is a more common material anyway. On an ideal endgame party, Levatine is easily the better choice as Tyrell's weapon.

Cultural References
Excalibur (derived from Welsh Caledfwlch, usually understood as hard-cleft) is the sword of the mythical King Arthur. Owing to its fame, it appears in several other games.