Moon Swords are given as gifts by the Red Emperor to those he feels worthy. It is known that Jar-Eel carries two one-handed versions, the Red Emperor has a Moon Sword but never uses it, the High Priest of the Crimson Bat has a Moon Sword as does the head of the Bloodspillers cult.
As Moon Swords only work for their owner they may not be gained through conquest.
The Scimitar has the same AP as an iron scimitar and acts as a runic weapon.
The owner may cast a Truesword on the sword once per day except when the Moon is Dark. This spell is provided by the sword itself. On days of the Full Moon, this spell lasts for 1 hour.
On command, the Moon Sword will glow a bright red, illuminating an area of 50m diameter.
A Moon Sword does special damage, depending on the Phase of the Moon. The scimitar does 1D8 + 1 on Dark Days, 2D8 + 1 on Crescent Moons, 3D8 + 1 on Half Moons and 4D8 + 1 on Full Moons.
Once per week the owner of a Moon Sword may call forth a Lune from the Sword. Each personal MP expended (not from POW Spirits or crystals) increases the size of the lune by 1 cubic metre. So, expending 10 MP calls forth a lune of 10D6 POW. This lune will remain summoned for 1 minute on a Crescent Moon Day, 5 minutes on a Half Moon Day and 15 minutes on a Full Moon Day. The Lune must be commanded as usual with Command spells which the Sword does not supply. Once summoned, a lune may not be resummoned until the next Full Moon.
Within the Glow Line or within a Glow Spot, the Moon Sword will function as if the Moon were Full. This makes them extremely powerful within the Empire proper. The Truesword spell affects the Sword fully, so on a Full Moon a Truesworded Moon Sword does 8D8 + 2 damage. If you play special damage as RQ2, the Moon Sword does 8D8 + 2 on a slash or 16D8 + 4 on a truesworded slash when the Moon is Full. Some people may feel that this is excessive, but one has to bear in mind that these Swords are generally given to Heroes as personal gifts from the Goddess.
As trophies, Moon Swords are worth around 10,000L.
Here are the statistics for a 2H Scimitar, given in both RQ2 and RQ3 formats.