Deep Lancilin

"This means that each of the twelve weapons were made with something in common. They're not mere things that were found across the islands. Lancelot had his eleven allies before he found twelve weapons. That's where this comes into play. I don't really know what its called, but each of the weapons that you lot have brought us have it. A liquid, held inside of whatever the damaging point of the weapon is. See, Galahad's axe, Bor's greatsword, Degore's cannon. They each have this trace liquid in them, which powers our Great Weapon. That's the point of them. It's not like the weapons are made out of it - it's simply that they are powered by it,"
 

- Doctor Lethlec's research notes on The Great Weapon

  Lancelot's conquest saw great results in the development of artificial magic weapons. The usage of natural magic has been utilised by smiths, enchanters, and other sorcerers in order to create magical items. Other than that, however, it's rather hard to create a magical item without the use of the magic found within the world. The only other form of wide-spread magical items that can be found, are the ones that are found naturally. That was, until Lancelot had his greatest physicians and scholars study the utlisation of Deep Lancilin. Found within the Lancein military training camps, Lancelot had eagerly used the liquid in as many ways as his mind could come up with. Eventually, he had channeled it into his spear, which gave him greater power. He had no elemental affinity at the time, the king simply being the most powerful warrior of his kingdom.
  The liquid itself, azure in colour and as free-flowing as water, and is found in abundance in a singular cave system that exists below Lancelot's residence. The liquid is unknown to practically everyone who does not live in the Thevagon Isles. 
    Other lords of the isles were given similar boons with their weapons. Degore was given a weapon that had influenced the power of his cannon. He could fire heavier items, whilst having an extremely light weapon. The proportional weight of the weapon was different for all who had wielded it. Degore was capable of holding it as if it had no weight at all. He could load it with blocks of pure tungsten, and fire it without any worry.