At the cave where Aearil perished, you were confronted by Mordrambor, and Saija revealed herself to actually be Amarthiel, once again using her powers of deception. You did, however, recover a ring-fragment, while Mordrambor and Amarthiel fought.
'This ring-fragment should be brought to Elrond of Rivendell, for he is wise in matters of the Enemy. A Ring of Power, however minor, is a dangerous thing.
'Give Master Elrond my gratitude, for it was in his care that my progeny were raised. If any of my line remain, speak well of me to them and bring them hope of great deeds to come.'
Elrond is in the library on the top floor of the Last Homely House in Rivendell, in the Trollshaws.
Arvedui confirmed that the ring-fragment was the lost half of Narchuil and bid you take it to Elrond in Rivendell.
Aragorn is in one of the guest rooms of Elrond's House.
Elrond bade you speak to Aragorn of your meeting with the shade of Arvedui, his ancestor.