The one thing that's annoyed me enough to make an account here just to ask about it is that the rules imply an ability to choose traits, but there's no xp price for extra ones. I want to make a character that starts out as a mutant, so how much would bonus traits cost?

As indicated in Chapter II: Character Creation , player characters may acquire certain Traits as a result of their origins, experience or other factors that make them who and what they are.

- Black Crusade 139 on Traits

Would this be what you're referring to? If you want to start as an extra mutant-y mutant in [black Crusade], the most mechanically supported method would actually be to hail from one of the other books. For example, [Dark Heresy - The Radical's Handbook] has the [Hive Mutant {Home World}] option as a "canonical" (I use the word lightly) way to pick up a select few mutations. From there, use the [Transferring Characters {Sidebar}] on Black Crusade - Core 281. This method has the side effect of creating statistically superior characters though, mainly because of how cheap Talents are in the original Dark Heresy. May or may not be a good thing.

Other than that, starting with certain Traits is pretty much just GM fiat. I personally don't remember any method of buying Traits directly from any of the games.

That seems like a stupid oversight. Maybe I'll just use DH backgrounds for my BC characters, then.

I agree that it seems like a stupid oversight that there are no "normal" mutations in Black Crusade, and that despite the "power level" of the game being very high, character creation is actually quite shallow - not being able to start with basic mutations, such as having been mutated before becoming a disciple of the chaos gods is odd, to the point where I wouldn't even have minded to see "Mutant" as an archetype just to make up for it - it certainly seems to be a archetypical way for someone to become involved with chaos, at least.

But there's never been a way to gain Traits as Advancements, nor other aspects such as mutations (or, to use BC terminology, Gifts), nor should there be. Traits are inherent to a character's being in one way or another, and is no simple result of applied life experience, although experiences in life can no doubt result in such, represented through gameplay and character growth.

If you've got access to other books, talk it over with your GM. Most reasonable GM:s will no doubt allow you to take some of the less insane mutations on creation, in exchange for experience.

There are combinations on creation that may result in an immediate roll on the Gifts of the Gods table, but depending on what one wants to play, that might feel incredibly contrived (psykers get 1d5 Corruption, Betrayal gives +5, Greed gives +4, Regret gives +5, but those are all Disgraces. Motivations, Innovation gives +2, Nihilism gives +5, and Violence gives +5.

So simply taking Betrayal and Violence, or Regret and Nihilism, will guarantee you a starting Gift of the Gods.

As a GM myself, my solution to your problem would likely be to create a new Disgrace, something along the lines of:

Taint

Marred by mutation and marked with a spiritual weakness, taint of the unwilling flesh is an ongoing fact of life for this character. Whether blasted by the powers of the warp in his youth or so blessed in his elder years, the heretic was touched by the fates long before he at last set foot upon the path for glory. Starting Corruption: +5 Corruption. Tainted: The character rolls once on a generic mutation table. With the GM:s permission, he may pick a generic mutation or a Gift of the Gods appropriate for his character. This mutation is always unaligned. Marred Spirit: Whenever the character rolls for a Gift of the Gods, he counts as having -1 to his Infamy Bonus.

That seems like a stupid oversight. Maybe I'll just use DH backgrounds for my BC characters, then.

By far the better option is to simply ask the GM if he'll somehow let you take a mutation on creation.

Piggybacking on [Fgdsfd]'s post, try to play the logic angle when you talk to your GM. Show him this thread, these comments, and let him know that [black Crusade]'s character creation is, ironically, ill-suited for creating "true" Black Crusade characters. [black Crusade] is the time, if not THE time (extra emphasis), to spread your wings with these crazy things that don't have a place in other settings. The written rules just don't support that vision.

Thanks for the help. I'll have to remember this in future

We use WHFRP2's tome of corruption for mutations. It fixes this crap.

(Its aligned tables are d100 anyway, so mostly translate directly. The d1000 is the one that may require some houseruling regarding infamy. We made it so undivided goes through the alignment tables in turn, for example.)