Ashalle is the guardian of the Dalish Elf Warden, and only appears in a Dalish Elf playthrough.
Background
Ashalle was a friend of the Dalish Warden's parents. After the Warden's father was slain and his/her mother disappeared, Ashalle raised the Warden among Marethari's Dalish Clan.
Involvement
Ashalle plays a minor role in the Dalish Elf Origin. After awakening from a coma, the Warden can speak with Ashalle at the Dalish Camp. The Warden can persuade her into finally telling about his/her parents, and will provide a key to a chest containing an Heirloom Necklace.
She reappears once again at the very end during the Post-Coronation, if the Warden survived the battle with the archdemon.
Trivia
Ashalle is not with Marethari's clan for Dragon Age II because she is still in Ferelden, managing the Dalish boon.[1]