The Spear Luin was originally forged by the god Lugh for use against Balor of the Evil Eye. In other versions, the spear was brought by Lugh from the city of Gorias, one of the four otherworldly cities in the 'Northern Islands' from which the Tuatha Dé Danann came to Ireland.
It was this spear that won for Lugh the epithet Lámhfhada, the 'Long-handed'. Whoever wielded it in battle would emerge victorious.
It was said to be so intensely hot that it had to be kept point-down in a large barrel of water (namely the Dagda's Cauldron Coire Ansic "Un-dry") so as not to burn down the place in which it was held.
Some legends state that the Spear constantly dripped blood.
A different spear of Lugh, the spear of Assal, was brought back to Lugh by the sons of Tuireann in atonement for their killing of Cian. When thrown in battle, uttering the word ibur, the spear of Assal always hit its target; it returned to the thrower on uttering the word athibar.