10 Most Rewarding Evil Playthroughs In Gaming

One of the features that defined Fable was Alignment, which affects how the Hero looks and how they're perceived.  Excessive eating causes them to gain weight. NPCs find the Hero intimidating, noble, or attractive, depending on what clothing they wear.

But the most important aspect of this mechanic was how good and evil deeds affect the Hero's morality. You're rewarded with Good points by saving villagers and you're bestowed with Evil points by eating Crunchy Chicks or by forcing villagers to go to work. (Yes, really.)

The Morality system is very black-and-white, so it's obvious what should be done. But the faster the "Hero" gives evil a shot, the sooner they'll realise that being bad... isn't that bad. 

Butchering innocent villagers offers more XP than the average monster, making levelling up a breeze. Dark magic is more powerful and can hit more targets, which is a godsend when attacked from all sides. If the Hero wants to wield the most powerful weapon in the game, all he has to do is murder his sister. (To be honest, they weren't that close.)

Also, there's no major disadvantage to being malevolent. Performing heinous acts will catch the authorities' attention, but it's nothing the Hero can't fight his way out of. And if you feel bad that the locals live in fear, you can always cheer yourself up with a good old-fashioned massacre before stealing their stuff.