This is the first episode of the Tallis series, set in the Dragon Age universe (specifically the second installment of the games). Written and starring Felicia Day, it is a great spin-off that inspires fanfic writers everywhere to never give up on their craft! Eventually, Bioware took on her character and added her as cannon to their games with the DLC Mark of the Assassin.
Seriously though, I sat with my draw dropped for the longest time when I learned that the awesome DA DLC that the boy and I played was after she wrote her character. She wrote the character, not Bioware. I love it.