I have a short question. That is just how ignorant of Chaos are the Tau? Could a group of Chaos Space Marines approach the Tau, sell them a line about being Space Marines who left the Imperium and now have seen the wisdom of the Greater Good and expect to be accepted, even if perhaps grudingly by the Tau?
The scenario I'm thinking about is that a group of followers of Chaos have infiltrated the Tau to make the aliens do some heavy work for them. Could this work or would the Tau be on their guard since they've have hostile contact with the Stigmaticus (or whatever they are called).