[@Necroes] Well....  There are a few events not in Urgrugg's favor. One, timing. I don't think a shear split second is reasonably long enough for him to conjure up a mass of psychic energy that big. 2. Urgrugg's spent a fair amount of energy already. I *know* psykers have limits. You can't conjure ass-cannons all day. 3. Cover. Certainly there's a fair level of forewarning that even non-psykers could figure out, especially given centuries of experience at war already. How much damage does Urgrugg want to do to the ships around him if the space marines dodge? How about if the two space marines separate? Then Urgrugg could only take out one of them, leaving the other to finish him off. 4. Also, the warp might just tell you to go fuck yourself at any given time you call on it. Urgugg could totally call a soul-devouring fiend into reality and we all die. ...

And I'm not sure that the majority of players know much about the table top game. Most people here that I have met, are novel readers and wiki readers.... and youtubers. We're young, and we don't have money. :P

[@Klomster] And you got shot at because you're a heretic. Now shut your vox-hole, heretic. (jk)

In conclusion, I do think you should back down on your powers, or at least handle them with less certainty. Don't do game-level interpretation. No player character should be able to take on an army, nor pass through a spacehulk with zero fear. That's just not even near the level of the rest of us. I feel like yes, Urgrugg probably could kill a couple of space marines, I mean they have librarians for a reason, but it shouldn't be no-contest in an rp. 

I'm glad JB has stepped in here, because we needed to talk about this. I hope we can all come to an agreement on what Urgrugg's limits are.