I tried another way to kill Isobel.
This time I teamed up with the Harpers and Isobel and defeated Marcus and the Winged Horrors. Looted Marcus ' body. Talked to Jaheira and Isobel who told me again to go to Moonrise and eliminate Ketheric. Then went to camp for a long rest because all my spells were depleted.
In camp, the butler appeared again, gruesome scene, but I escaped the worst of it. He reproached me again for not having killed Isobel.
Leaving camp, I attacked Isobel and killed her swiftly and then.... suddenly we see Marcus flyi off with her. This definitely cannot be right.
It's not that I want Isobel dead per se, I'm mainly interested in the new scenes for the Dark Urge. But here something is definitely wrong. If I had known this beforehand then I wouldn't have had to waste 2 evenings trying to obtain an Isobel dead body to present to the Butler.
There are other incoherent things in the dialogues with Isobel and Jaheira when you have been in Moonrise and seen Ketheric on his throne before you come to the Last Light Inn.
But the promised price for Isobel's death seems unattainable.
