Neamhain's Powers?

I was wondering if there was any way to reactivate Neamhain's power for the finale. Can you leave, go back in, switch, then proceed? If you can, will Spear of God be a good strategy?

nope. eabha doesnt let you do that.

also you would need wings of rage to get Nuadha down from flight and his light sword and spear of light will kill you in single shot so.... meh...