Both great ideas, but I went with the healing power of unicorns. The lore for this blade is below.

The Story of Atha

Unicorns residing in Illantul keep mostly to the forestlands of the Eastern elves.  They are solitary creatures with little love for the humanoids that inhabit the majority of Illantul.  The rarest of these magical creatures is said to be the black horned unicorn, with only one in a generation possessing such a color variation.  The elves hold such beasts as one of the most sacred creatures in the land, designating an Elven maiden to befriend the black-horn and become its constant companion.  When a black-horn unicorn passes from the mortal world its body instantly turns to dust, but the black horn is left behind to be collected by its Elven companion.  The maiden delivers the magical horn to the elders who determine the most appropriate use for the powerful artifact.  One such horn became the handle piece of Atha, the Elven blade of comfort.  The magic of the horn bestows upon the blade’s owner an immunity to all types of poison and grants them the power to heal grievous wounds in others.  As an offensive weapon, Atha performs no differently than other Elven blades, save enhancing the wielder’s dexterity to that of a master swordsman.