Being evil in my opinion is most of all find solutions that helps you the most with no regards to others. And right now the game does a very bad job at that. You have the option to either kill the goblins for a possible cure to your condition or kill the druids and tieflings because bitchy drow lady told you to. There is no benefit for you. Why should you involve yourself in this conflict at all? And if you just wanna kill stuff cheotic style there are plenty of goblins to slaughter... So why?