Yes they are. And I've already finished the book lol
I just find Cain to be just about the best protagonist that I could hope for coming out of this kind of setting. His innate cowardice combined with his undeniable skill is just hilarious. And then you throw in the characters like jurgen and amberly? It's too good. I found myself on more than one occasion actually laughing out loud.
He's also the first character in the series that I have found to be somewhat relatable. His entire Outlook on the emperor, the imperium, and the administratum is perfectly understandable and believable. It doesn't come off as being too forced like it has been with other characters. He doesn't have the same blind loyalty and blind faith in the Imperium and the emperor. He has doubts, but he still clearly cares and is willing to do what it takes to do what he thinks is right.