Aro: Did your character sell their soul?
If you select that back story it's (supposedly) impossible to go higher than -20.

I've made one like this and it continually loses rep for normal actions oddly enough.

Hesusio: By "creatures" do you mean things like wolves, bears and boars (i.e. creatures that pose a threat) or things like chickens, rabbits, dogs and cows? Becuase I believe when it comes to creatures that don't attack unless you attack first (i.e. the latter category I mentioned), you aquire negative alignment for killing them.

I'm playing a good character right now and the only creatures I kill are the agressive species and it's done nothing to my alignment. Try leaving the passive animals alone and see if that helps. If not, you may have a bug.

Aro: You're certain the character is not wearing any items that give negative alignment?

Was thinking, perhaps if the enemy does not appear red in during combat (the little circle near their feet) when you attack it may count as us initiating the combat. We are evil for taking the first strike.

DamienVryce: When I mean creatures, I mean the aggressive type. To give an example, when I was attacked by the strange monsters near the portal that needs to be closed (forgot the name of that quest), my alignment went down by one. I'm trying to play a good guy and have never attacked anyone, always try to chose the nice responses in dialogue, and never attack domestic animals, just the monsters or bandits who attack me. My alignment as of now is around -20. I don't understand why, but I figured out it's when I kill a monster, my alignment goes down by one. I don't have any hexed items on me or my companions. I think it's a bug, but I don't now how to get around it and it's ruining my playthrough. I dont really want (or have the time) to start over. Any one ever heard of this kind of problem?

Waltorious: Can you give us some more info about your character? Stats, background, equipment, etc.? As others have mentioned, there's a possibility that some of your equipment or something could be causing this, so info about your character would help us diagnose the problem. There are definitely some "evil" magic items that, when equipped, can cause your alignment to drop.

On the other hand, it could be a bug. Are you using the unofficial patch? It's highly recommended as it fixes a lot of bugs.

Hesusio: Is your character cursed? That may be it and it wouldn't show up in the stat screen. Check your journal, there's a section for blessings and curses in there.