Sorry, but you do have to play an evil character to do the questline. The game even reflects this, as it adds to your infamy, and takes away your ability to use the chapels and wayshrines for restoration.
http://img.photobucket.com/albums/v90/subrosa_florens/oblivion/Oblivion463.jpg would tell you that the only reason others exist is so that she could take the pleasure from killing them. Its not like they are people, as she is. They are all just victims waiting to happen. That is why the gods put them there in the world. How can slitting their throats and smiling as the life drains from their eyes be immoral? That's just crazy talk. 
http://img.photobucket.com/albums/v90/subrosa_florens/oblivion/Oblivion463.jpg would tell you that the only reason others exist is so that she could take the pleasure from killing them. Its not like they are people, as she is. They are all just victims waiting to happen. That is why the gods put them there in the world. How can slitting their throats and smiling as the life drains from their eyes be immoral? That's just crazy talk. 



Well I used to feel this way, but with my last character who did the MQ, I actually started to miss the gates after he finished the quest. Now, The Grey Wizard (that's his name) is bored and living a country gentleman's lifestyle.
Then again my 200+-hours and my other 500+- hours playing sessions were very glitch-free & enjoyable... And I′ve found my installing-sessions quite enjoyable as well - anticipation is not the worst kind of joy. Ah well, maybe I just should have learned proper modding right at the beginning...

