Spirit of the Steel

Magic weapons are a staple of fantasy gaming, and for every Excaliber and Zodiac Spear, there are legions of mundane magic weapons, the innocuous Longsword +1 and other magical weapons only expressed as a weapon type and a bonus modifier. While such a display is anathema to fantasy writing, it is quite standard par for the adventure gaming course. While the notion of every magical weapon having a grand backstory, a mythical origin, and a hard to pronounce name, most of this is likely to fall by the wayside as the rugged band of heroes hack their way to gold, glory, and XP.

A Sword With No Name
Heroes wield mighty blades hammered by the gods, PCs tend to get a bit less unless games are incredibly high level or high powered. Descriptions of blades very by the type and style of sword, but certain aspects remain the same. The most common aspect being that the weapon in question is made of the best quality materials and is of the top quality the weapon maker in question is capable of. Apprentice work, flawed blades, and the like do not make it past the rigours of testing before the process of enchantment and bonding takes place. The second aspect that is similar is the presence of some sort of arcane script etched, carved, embossed, or otherwise made a permanent part of the blade. It doesn't matter if it is runes, elfin poetry, geomantic sigils, or eldritch symbols of power, the end effect is the same, a bonus modifier to attack and damage.

A Weapon of Two Worlds
Most fantasy settings work with some sort of multi-planar cosmology, ranging from a simple duality, to a wide spread cornucopia of planar realms running from elemental realms to exotic pockets of reality. The true purpose of the arcane script etched into the weapon is that it creates a bond to this spirit and energy filled alternate realm, a conduit for the natural flow of magic. This makes the weapon in question real in both the material world and the spirit world. As such, a wound inflicted by the weapon is able to overcome magical and supernatural abilities, penetrate normally impenetrable armor, and cause more damage than would be expected.

The power of the weapon is determined by the skill of the etcher or engraver who works the arcane writing into the weapon. The more skill and time they invest into the etching or engraving, the more potent the weapon in question. It is very likely that the actual empowering symbols will be surrounded by ornamental symbols, artful etching and the like. Some of this is purely ornamental, the other aspect is that it prevents someone from merely looking at the length of the engraving on a weapon and determining the magical strength of the weapon.

Who Makes These Things?
Mundane magic weapons might not actually be considered magical weapons, since they do not evince any sort of magical ability other than a magical aura and increased ability to do damage. As such, these weapons could be made by practitioners of Low Sorcery. True magi would hardly consider making such lowly weapons beneath their ability, leaving the making of these weapons in the hands of enlightened weaponsmiths and enchanters of the Low Sorcery method. As such a village with a decent forge could have one or two of these class of weapons, heirlooms of masters of the forge, or possessions of the local gentry and lower echelons of the nobility.

Applications of Force
You Can Have it, But it Will Cost You - Sometimes a player and subsequent PC will want a large and nasty beat-stick for taking down monsters and getting XP from large and nasty foes. Such a weapon can be procured without all the drama of hunting down a legendary weapon, dispelling curses and all the other baggage that comes with getting such an awesome and likely broken weapon. The PC/Player can commission a Sword +3, or Sword +5 but there are two things that can constrain said player. The first being that such a weapon will remain expensive, likely several thousand gold pieces to tens of thousands of gold pieces to cover the materials and labor of both a master bladesmith and a master enchanter of low sorcery. Secondly, such a weapon will take time, 1D4 + 1 Month/per level of power. The PC is saddled with both a large bill, and subsequent downtime waiting for the weapon to be made.

Tough, But Not Unbreakable - Magic Swords don't get broken, and in the rare cases where they do (Narsil/Anduril) it is a legend worthy tale behind their reforging. A common Sword +3 can be broken, and while it is a blow to character, it isn't derailing to the story, plot, or history of an established setting.