I just posted up a resource on Dark Reign for an idea I found recently and remixed. The link is http://darkreign.org/downloads/01-09-2015/exorcism-remastered .
Someone originally made their idea of an Exorcism psychic discipline. Unfortunately, they made a creation that, I'll say harshly here, looked quite juvenile. It was a discipline for banishing Daemons, sure, but it had the Psyker loading up on meeting prerequisites for a final shebang that prevents Daemon rifts for 100d10 years in a 100km radius or something, that requires the Psyker losing all his powers but gaining the Untouchable background and half his spent experience back.
Regardless of that implementation, I really liked the idea of an anti-Psyker Psyker, and so I trolled a lot of Lexicanum and WH40K Wikia for a better sense of how it could be palatable to a reasonably serious Dark Heresy player. I settled on the idea of a discipline focused on, well, discipline: Exorcists look at the Warp as a problem more than a power, and so exercise restraint in how they apply their abilities. Biomancers look to use warp energy to improve the human form, the Telepaths use it to control other humans, Diviners use it for guidance, and the Kineticists use it to rearrange their environment. No pre-existing discipline has overlap with Exorcists, who use warp energy to save humans from the dangers of warp energy.
Go ahead and follow the link to read up on the actual abilities themselves; you can download the .docx there, which I think is more legible than the site's formatting. I'm looking to know whether people find the idea as intriguing as I do (please read the abilities, not just my little blabber on this post; I didn't say everything I want to here) so I know if I should keep iterating on this idea (it's only at v1.0) and I want to know what's glaringly overpowered (or underpowered) in it so I know how to keep iterating on it.
Thanks!