Eventually the battle turns in favour of the Tuatha Dé but Nuada of the Silver Arm is slain by Balor of the Evil Eye and the stage is set, in the great tradition of all sagas, for the final confrontation as Balor was the Fomors most terrible weapon and now the time had come to use it, for Balor could hear the taunts and jeers of the IL-Dána:
"Balor, I have come to take your life" he cried.

"Who is this babbling youth?" asked Balor of Caithleann his wife.

"He is Lugh the Il-Dána," she replied, "the son of your daughter Ethne and he has sworn to destroy you."

"Lift up the lid of my eye so I can see the braggart who is taunting me," said Balor. Now the Evil Eye was no ordinary eye but a deadly weapon that was never opened except on the battlefield. It was "a ruinous venomous weapon" that needed four strong men to raise the lid from the eye with a polished grappling iron hung on massive wheels and pulleys.

As the Evil Eye swept the battlefield its deadly gaze destroyed all who stood before it; whole troops of warriors lay withered in its wake and the tide of battle turned against the Tuatha Dé Danann. But Lugh had prepared himself well for this moment and cast a powerful "Lightning Weapon" (some accounts say "a great sling-stone") that drove the Evil Eye through the head of Balor and turned it back on the army of the Fomor so that all those near it perished.