Alessa is a woman in Dragon Age II who lives in Kirkwall.
Involvement
When Hawke goes to search DuPuis' estate during the quest Prime Suspect, (s)he eventually finds Gascard DuPuis with a woman named Alessa. Gascard begs Hawke to spare him, claiming that several years ago his sister was killed by the true murderer who now roams in Kirkwall. He moved there to avenge her, and took Alessa hostage since she was the next victim. When Alessa claims Gascard hurt her, he explains he only took her blood in order to be able to trace her thanks to blood magic, should she be abducted. Alessa eventually flees for her life out of the estate, with Gascard fearing that she will link him to the murders.
In the quest All That Remains, Hawke will find Alessa's body in Quentin's hideout in the basement under the foundry in Lowtown.