Now how compatable are stats from Warhammer Fantasy Roleplay to the Warhammer 40k games? Could I use a daemon from that game in 40k? What about different fighting styles? Talents?

Now I think Magic is different for Warhammer Fantasy due to the Chaos Gate. What if I had a world with a similar situation? Could I adapt the Colleges of Magic? What about gods from the Fantasy system that were not slain in 40k? Could I have actual Priests?

I don't have the Warhammer Fantasy Roleplay system yet and was wondering about getting it as source material (or at least hitting up my local library)

WHFRPG 2nd ed is the ancestor of WH 40k RPG, so there are a good hand full of similarities. However, there are also some differences, especially with things like how many combat actions characters get and the mechanics for dealing with that and how Criticle Damage works. You should still be able to convert without too much difficulty if you understand the differences. To my knowledge, however, there is little similarity between WHFRPG 3rd ed (the new stuff) and WH 40k RPG.

Yeah, 3rd edition is completely incompatible with 40k RPG. The systems are entirely different. 2nd edition however is the system that Dark Heresy grew out of so there are many similarities. Unfortunately they aren't really compatible. They use basically identical basic rules, but the stats are built on a different scale. For example, orks in wfrp have a toughness of 40 something. In Dark Heresy they have 40 something but with unnatural toughness, which makes them twice as resistant to damage. The Magic system is actually basically identical to psykers in Dark Heresy (Rogue Trader and Deathwatch are very different indeed), but many of the powers do very different things (and stylistically magic is more like Sorcery in Dak Heresy).

Basically I wouldn't get them for background for 40k. However there are many of very good sourcebooks for Dark Heresy.

borithan said:

Mhmm, Tome of Corruption has some wonderful inspirational stuff on the backgrounds and descriptions of the Chaos Gods as well as their cults and demons, though. They are pretty similar between the two settings (given that the WFRP world was originally supposed to be a planet in 40k some time ago, or in fact may still be as the connection was never officially denied).

Of course, Black Crusade will likely contain much information of similar nature - but not all of it.