GM question

[Tamashi Hasu]

I'm creating a magic based campaign, and my one PC wants to make a mercenary that hates Magic, and wont help out the party because they're not the ones who employed him, and won't give me his backstory so I cant ask him if what he does is how his character would act. What can I do?

[Nyerkh]

So many questions ...

The real answer is : talk to him. Find out what he wants to do and why.

For a more long-winded version : Ask him what the point is ?
Making a character to very specifically not participate is a tad weird.
"Hiding" a backstory from the GM serves no purpose. Might as well not have one - not everyone is defined by their past. But even then, knowing that would be nice.
Why would the rest of the party tolerate him ? Why is he a part of this to begin with ?

Conflicts and tensions inside a party are fine. Fun even, if handled well.
A player being an annoying diva isn't, ever.
Which it is you're dealing with is something you might want to figure out fast.

Also, in doubt, if you don't want to deal with a character like this, "No" is an answer you're allowed to use. Not every concept is fit for every campaign.

[Duamatef]

My answer would be:

1) I'm the GM, so if I don't know the backstory, it doesn't exist, since I have to say okay to begin with.
2) If you want your character to not work with the party, then the games are going to be boring for you because I'm not going to make everyone else sit around while your character does his solo thing, and since you won't be with them you won't be involved in the action or the rewards.

In other words, as Nyerkh said "No".

That said, I also tell my players when they join that their character doesn't have to be nice or liked, but it cannot be disruptive to the party.

[DungeonmasterCal]

Why? Why is there always "that guy" who won't go along with the campaign set up? Why?

[arkham]

I would say, "Thanks for the NPC, now make a character that will participate in the game."

[Daw]

I think you may need to go further. His original concept is a game disrupter. Is his next character going to be a more underhanded version of the same? Have you any idea why? Is there a history here?

[Java Man]

I'm a bit less subtle. I would tell this bozo to quit their nonsense or find another game. Creating an intentionally disruptice character and playing 'secrets' with the GM are both booting offenses at my table.

[Tamashi Hasu]

Thanks for the input guys