[Mathai]

I havent yet read the Ravenor series, so I cant make a fair asessment of his abilities in comparison to Eisenhorn's come the third series. But, if I had to choose with hero and his retinue would emerge on top, I'd have to go with Eisenhorn. Not just for his own wily ways, but because knowing him he will have only improved his control over his trump card that is Cherubael. (I really loved how his more tightly controlled daemon-host body was still quite snarky, those last few pages were great.) I dont doubt Eisenhorn would be unwilling to release that daemon fully again only to once again ensnare him when it did its thing once more. Though I can also see it where Ravenor's side actually manage to defeat the bugger, at great cost to their own of course.

 

[Mathai]

Actually MuSigma, I dont think it would be as simple as the Inquisition telling one of them to go after the other. I believe that both of these people, Eisenhorn and Ravenor, are of strong enough will and independant in thought enough that they wont just blindly follow something external anymore.

If one of them genuinely fell to Chaos, not just use it to fight the enemy like Eisenhorn does, then it would not be shamefull for the other to want to save their friend in the only way possible at that point. Neither wants to become another Quixos. Because at that point, nothing they did matters as much as the potential damage they could do to that same Imperium they both love.