Shaman Karrakh quest chain..?! (Spoilers)

[taltamir]

without turtle you MUST kill him. so no shop...

There are two choices:
1. Use turtle:
option1: you do use the turtle, you get crystals and the battle is easier.
option2: you don't use turtle and the battle is harder.

2. Letting him live (only available if you used turtle):
option1: you kill him, get the skull, XP.
option2: you let him live, get the skull, and he opens a shop.