When discussing the loss of Sten's sword with him, Sten says that the blade was forged specifically for his hand alone. However, the description of the sword says that it was recovered from the invasion of Thedas and granted to him upon receiving his mission.
Sten also mentions that the sword was forged from a rare material known as blue steel. Unlike Starfang, however, its material is simply referred to as generic steel rather than informally listed as a separate material type.
Asala is one of the two swords featured in the Start Game menu screen; the other is Yusaris. (Yusaris is on the left, and Asala is on the right.)
Despite its importance, Asala can be sold or disposed of after completing the quest, without any reaction from Sten.