[The Barrow-Wight]

In the books, Arwen's brother deliver a banner to Aragorn, so it's not so (totally) unbelievable that Arwen could accompany them carrying Anduril. But the Grey Company arrived after the battle of Helm's Deep, so Peter Jackson would have to seriously skew the timeline if he wants to inject her into the battle there. If she does arrive in the proper timeframe, that means she would accompany Aragorn through the Paths of the Dead and arrive late at the Battle of the Pelennor Fields... too late to slay the Witch King as some have suggested. But I'll guess we'll have to wait and see.<P>Either way, though Strider carried the shards of Narsil with him, he must have had some other weapon with him. You don't become a great warrior practicing with half a sword.