The Teifling fight on the side they do more often as Evil seeks to pillage kill and enslave, all of which I am sure they would rather not be victim to. The Drow are fighting for evil as they have simply taken the opportunity to increase their power in the lands through war with good. While they are not allied with evil the saying ' [i]The enemy of my enemy is my friend [/i]' is suitable here. [@ViolentViolet]