Sorry Dr. it's been done.
I did something VERY similar to this in an RPG that I never finished. But, I had that system completed. Here is what I did:
I made a pylon to represent the "Holiness". It was on a scale of 1-100.
Let's say you were offered a quest. If you say no, it drops your score "X" amount of points. Once you got to 30/100 you started becoming "evil". NPC's would reply with more of an edge. I.E. Instaed of "Hi Bill how are you?" they would reply with "What the hell do you want!? Pig!". But, if you did do the quest it would reais your deaths "Y". If you got to about 70/100 you were considered good. So, the NPC's would be nicer to you.
The only bad thing about it is, the strings. You use a LOT of strings. Because, I changed almost the entire game with this system. Shops, People, Enemies, Friends etc... It was a cool system, I just never finished the map. But, I am doing something similar in my current map. I WAS going to keep it secret. But, you just had to say something!
... I am making the system the same way. But, I will not tell you what it;s for. I don't want to spoil anything!