Dark Heresy 2e and Dishonored are viable only if you have the core book at least. The Legend in the Mist Demo is a free download.

And, thinking this through, I have zero experience with Dishonored, either with the video game or the RPG. So, let's shear it down to...
¤ Legend in the Mist, or
¤ Dark Heresy 2e

Do you have any preference between the two?