I have trouble translating my RL morals into a fantasy world. Good and evil are just one perspective. Of course the Durge has a past, but he certainly has the choice to reject that past, to consider it terrible. One might then ask how moral it would be to kill this Durge because of a past he now rejects. The Durge, similar to Astarion, is the tool of a more powerful creature, therefore they have a very deep bond and have empathy and understanding for each other. Can the Durge resist the “Urge” and elude Bhaal? Personally, I think the perspective that the Durge is fundamentally evil and insane is too simplistic.
Personally, I prefer the evil Durge and even this shows empathy. Thinking of the Durge as a Murderhobo is just a very simplistic picture of him. He is definitely a “private person” if Bhaal doesn’t control his body and mind. Of course the Durge was/is insane, that's in the spirit of the matter,that he is less able to resist the “urge” he gives in to. Only completely "insane" Bhaalspawns will get the Slayer form. But the dagger and the worm have reshuffled the cards and new possibilities and paths arise. I can also be evil and resist the Urge and thus Bhaal, I can betray Bhaal. As Sceleritas says, the worm in the Durge's brain is a gift that an evil Durge can certainly use.
The companions' reactions to the Durge's actions are rather reserved. I also find it strange that I first tell everyone and their grandmother that I have an urge to kill. Astarion is the only one who reacts more or less strongly to the Durge's actions. The more evil you are, some of his texts change. All companions fear the Durge to a greater or lesser extent.
In this mind "So rise, Challenger of Gods"
