Unlock the following Legendary weapons by performing the corresponding tasks:
HOW TO UNLOCK
Ageless- Before you choose a new King in Orzammar, click the King's throne.Set three party members on pressure plates, and a fourth to click thethrone again. Then, kill the dragon. Marjorlaneses Recurve
Beat Leliana's quest.
Staff Of The Magister Lords
Purchased in the Wonders Of Thedas in Denerim.
Get the random encounter with the crater, then take the Starmetal to Wardens Keep.
Defeat Loghain's general.
The Rose's Thorn
Can be purchased at the shop in Orzammar.
In Deep Roads, find the three pieces and then reassemble them in Ortan Thaig.
Purchase it at the Wonders Of Thedas.
Beat the "Statue" quest on the third floor of the Magi Tower.