The coils of the World Serpent
Huginn and Muninn
Paired Shortswords, With a bit of the Trickster about them.
Aesiri Swords of Dancing
On the first round of melee these weapons are +2, on the second +3, on the third +4, and on the fourth it is +5. On the fifth round, they drop back to +2 and the cycle begins again. In addition, after four rounds of melee their wielder can opt to allow them to “dance.”
Dancing consists of loosing a sword on any round (after the first) when its bonus is +2. The sword then fights on its own at the same level of experience as its wielder. After four rounds of dancing, the sword returns to its wielder, who must hold it (and use it) for four rounds before it can dance again. In other words, it is loosed to dance for four more rounds, going from +2 to +5, and must then be held by its wielder at a +2 state and physically used for four successive rounds of melee combat.
When dancing, the sword will leave its owner’s hand and may go up to 50 feet distant. At the end of its fourth round of solo combat, it will move to its possessor’s hand automatically. Note that when dancing the sword cannot be physically hit, although certain magical attacks such as a fireball, lightning bolt, or transmute metal to wood spell could affect it.
Finally, remember that the dancing sword fights alone exactly the same as its possessor; if a 7th-level thief is the wielder, the sword will fight as a 7th-level thief when dancing.
Relieved of his weapon for four melee rounds, the possessor may act in virtually any manner desired – resting, discharging missiles, drawing another weapon and engaging in hand-to-hand combat, etc. – as long as he remains within 50 feet of the sword. If he moves more than 50 feet from the weapon, it falls lifeless to the ground and is a +2 weapon when again grasped.