[@Andreyich] If that happens, sure. If the Imperium decides to dedicate an entire strike force of grey knights temrinators to a specific problem, than anything short of a daemon prince is fucked. And even then it's debatable. So I don't really suspect that will happen all too often. 

 My point was more, this collection of characters is anything but bottom of the barrel up & comers looking to make names for themselves. We have space marines, two chaos infused ogryns, one of which is also a daemonhost, someone with their own ship and crew (numbering in the tens of thousands at minimum) and another with a rosette that gives cart-blanche to literally do whatever the F*** they want. He might be an excommunicated inquisitor, but it's not as if grey knights will teleport to him instantly the moment he uses his rosette, not that anyone would be able to track such usage anyway. By the time anyone suspected it was really him in the region he could easily get whatever he needed and GTFO. Possibly even condemn a world to exterminatus while doing so.

Now, i'm not saying any of this is bad, that anyone's character concepts are bad or that things needs to change. Far from it, I'm just pointing out that all things considered, an aspiring sorcerer putt-putting around in his own little escort ship with some thralls at his command wont be what tips this group over the cliff's edge of absurdity.