Vidofnir

Vidofnir, the Winged Lance, is an S-ranked Lance weapon acquired in Fire Emblem: The Sacred Stones, and is one of the Sacred Twins category of weapons.

As with all Sacred Twins, it has a boost to stats, which in this case is +5 to Defense, and is a Class Buster against Monster enemies. If Gilliam's defense stat is at 30, and he is wielding Vidofnir, his defense stats are 35 (thus making him nearly invulnerable to iron weapons.)

Stats

 * Uses: 30
 * Might: 15
 * Hit%: 80
 * Weight: 11
 * Critical rate: 0
 * Range: 1-1
 * Cost per use: 0
 * Weapon Rank: S
 * Weapon EXP: 1

Etymology
This name only occurs once in Norse mythology, in the poem Fjölsvinnsmál, 'Vidofnir' is a rooster who sits in the tree called Mímameiðr. According to Wikipedia, the Mímameiðr may be associated with the forest in which the last remaining humans will seek refuge during Ragnarok, the Norse apocalypse. This seems fitting for a legendary weapon.