Ancient and Legendary Weapons:
There are five known "Ancient Weapons" in the world of Guild Wars. These include:
-Cauldron of Cataclysm
-The Scepter of Orr
-The Staff of the Mists
The origins of all these weapons are unknown, but some of their history is known, and some of their powers.
Cauldron of Cataclysm:
This is seen only in Pre-Searing Ascalon in The Northlands. Although a copy of it can be throughout Ascalon - such as at the bonus of the Ruins of Surmia mission. Another copy can be found in the Crystal Overlook in the Desolation.
According to the Ecology of the Charr, this object was given to the Charr by the Titans and is said to be older then the Titans themselves.
This is what caused the Searing, and could easily be considered the most powerful Ancient Weapon - at least in terms of it's connection to the magic school of Destruction.
Sohothin and Magdaer:
The twin swords that have been passed down from king to king in Ascalon longer then we know. At first believed to be simple Fiery Dragon Swords that all of Ascalon's Royalty and Royal Guards wield, now for sure to be two ancient weapons.
The power of these two weapons are unknown, however, one thing these swords can do is known. According to the Ecology of the Charr, Adelbern wiped out all of his own soldiers and the enemy Charr at the Battle of Ascalon City, and raised his soldiers as restless spirits. It is said that a giant white flame in the shape of a sword was cast through the City which killed everyone.
Whether raising the fallen soldiers as ghosts is a part of the power of Magdaer's power or occurred due to dying so fast - and therefore becoming restless and unable/unwilling to go to the Rift - is unknown.
It is believed that the only thing to bring rest to these spirits is the return of Rurik's sword, Sohothin, to Ascalon City. However, if it is in fact that the ghosts are simply restless and not bound to the sword, then this won't work.
So while Sohothin's power is unknown, Magdaer's power seems to lie in the school of Destruction and Denial magic (Destruction for killing, Denial for preventing rest to the spirits).
The Staff of the Mists:
The sister staff to the Scepter of Orr. True origins are unknown, however it is known that the Staff of the Mists, along side the Scepter of Orr, was given to the human kingdoms. By whom is unknown, as is the time frame. The power of these two staves caused constant rivalry and the gods were forced to intervene. At which point, they were lost to time until very recently. (source)
The Staff of the Mists has the power to bend the physical world. By doing this it can heal the wielder and harm the wielder's enemies. It is also believed to have the power to expand one's lifespan.
The Staff of the Mists can be linked to two schools of Magic:
Preservation - healing the wielder.
Aggression - stealing life from the wielder's enemies.
Unfortunately, this staff is now destroyed.
The Scepter of Orr:
The most popular ancient weapon of them all. The origins of the Scepter of Orr is the same as the Staff of the Mists, given to ancient human kingdoms, caused rivalry, forced gods to intervene, lost to time until recently.
This staff - I stay staff due to it's size, not name - has the power to bend the mental world. Through this, acting a similar way to the Staff of the Mists, can increase one's concentration, mental abilities, and knowledge - theoretically. It is known that it has the power to increase one's energy, whether through the energy pool or through energy regeneration.
The Scepter of Orr can be loosely linked to the two other schools of magic that the Staff of the Mists is not linked to:
Denial: Although would be better linked by energy stealing (commonly referred to as e-denial), this would easily fit the whole idea of giving energy, both seen abilities of the Scepter of Orr.
Destruction: Destruction, the school for Elementalists, seems to require high amounts of energy, therefore the Scepter can give such requirements to the weilder.
It is believed that the Scepter of Orr can control Undead and the Titans. While this is possible - by controlling the spirits of Undead (their source of animation) and the spirits of Titans (which is what Titans technically are) - this is not proven due to the Lich being the one to show control of the Undead and Titans. The Lich controlled Undead long before obtaining the Scepter, and as he was a follower of Abaddon, Abaddon could have ordered the Titans to simply "follow the guy with the stick."
The Stormcaller is a third legendary “weapon” of Ascalon. It is a giant horn built into the side of a cliff near Rin. It is believed that when used, it would save Ascalon. However, this is now known not to be the case, as Ascalon falls after the Stormcaller’s use.
This object has the ability to summon rain and water upon the land. It is very likely that the Stormcaller will be used by the Charr to hasten the renewal of the land after they retake the land.
Although not really weapons, these Scrolls are very powerful objects. They were created between the time between 1 BE and the creation of the Bloodstones, and locked up underneath Orr, supposedly for safe keeping – however, it is thought that they were kept there by the Vizier after being corrupted by Abaddon.
These scrolls were used to destroy Orr and turn Khilbron into a lich – if he wasn’t already one prior to the scrolls’ use.
Along with the aforementioned, it is known that these scrolls contain magic from when all four schools could be wielded at once – meaning that these scrolls contain the magic of Preservation, Aggression, Destruction, and Denial.
Hammer of the Great Dwarf
The Hammer of the Great Dwarf is yet another legendary and powerful dwarven weapon. This weapon has the power to channel the power of the Great Dwarf through the dwarves who go through a ritual that is shown in the Eye of the North campaign.
Old and Powerful Weapons
Despite its name, it is not very old. Created less then two hundred years ago, while not old, it is powerful. This weapon was the bane of the Elonians that resided within the Arid Sea. During their internal struggles, an unnamed person created this weapon to finish the other side of said struggles. This weapon ended up killing them all.
Originally intended to knock down the Lonely Vigil, it now has no use in the GW world, but is known as the weapon that finished of some, if not all, of the Elonians’ squabbles.
Urn of Saint Viktor
The Urn of Saint Viktor is a Kurzick artifact from two hundred years ago. It contains the ashes of the Kurzick hero, Saint Viktor – as the name of the relic implies. The urn has the ability to create a temporary “shield” around those near the relic upon dropping it.
Its ability is the opposite of the ability of the Spear of Archmorus (talked about below), which personifies the difference between the Kurzicks and Luxons. And, the object and power itself personifies the Kurzicks’ desire to defend rather than attack – as shown in various quotes and quests throughout Factions.
Spear of Archemorus
The Spear of Archemorus is a Luxon artifact from two hundred years ago. It contains the ashes (or simply remains – as the skull is seen at the tip of the spear) of the Luxon hero, Archemorus. The spear has the ability to damage all the nearby enemies of the holder upon dropping the relic.
Its ability is the opposite of the ability of the Urn of Saint Viktor (talked about above), which personifies the difference between the Kurzicks and Luxons. And, the object and power itself personifies the Luxons’ desire to attack rather than defend – as shown in various quotes and quests throughout Factions.
Despite its name, it cannot be used as an actual weapon.
Anvil of Dragrimmar
The Anvil of Dragrimmar is a, rather large, ancient Anvil. It was once used by the Great Dwarf himself to make powerful weapons. Due to its size, it cannot be *easily* moved from the Sepulchre of Dragrimmar. Its creator was Dragrimmar, an unknown creature – guessed to be a dwarf.
A slightly more in depths look can be found here.
Very little is known about this object. All that is known is:
1) It’s a staff.
2) It slows down the enemies of the one who drops it.
3) It is linked to the Mesmer profession (the symbol that appears over foes who become slowed down is the same as the one for imagined burden).
Through what is known, it can be suggested – although far from proven – that this staff once belonged to the Mage Lord Sybitha who once performed experiments in the Crystal Desert – at least to the extent of creating and/or releasing the Storm Riders.
This staff is in the possession of the Losaru Centaurs upon entering the Dunes of Despair mission, suggesting that they stole the staff for it’s power, possibly to use against the Storm Kin – as in The Ranger’s Path quest, it implies that the centaurs are enemies of the Storm Kin.
Palawa Joko's Staff
Very little is known about Palwa Joko’s Staff’s power. All that is known about it is that it has some importance as it was stolen by one of Joko’s generals after his imprisonment and he wanted it back.
Kathandrax’s Crusher is a legendary and powerful dwarven weapon. Its abilities and origins are unknown. All that is known about it, is that it is, or was, stored in the Catacombs of Kathandrax – within the Charr Homelands – and is a dwarven weapon. This supporting that whoever “Kathandrax” was, it was a dwarf.