I got this task where I should kill the "master thief" he should be in a bookstore in vivec..can't remember the name though...anyone who know where it is?..it's a the vivec fighter guilt mission

Jim Stacey can be found at Sinine Fralinie's bookstore in Vivec, Foreign Quarter Canalworks. There is a locked door in the back of the shop. Look there.

Do you REALLY want to kill him ? He might come in handy later in the game... as a friend.

yeah Jim's a nice guy and all, shouldn't kill him for, um i don't know the fighters' guild or something

If you have join thieves guild, I say don't kill him. however if you didn't. kill him anyway.

They need to have made it more apparent that there was an option not to kill him.

If he joined several guilds at the same time, he could have known.

ok thnx for your help... so if I havn't joined the thieves guilt it doesn't matter?

No it doesn't... but if you are a thief or you plan to be one, I urge you to speak to Precius Mercius, the figthers guild chief in ald Ruhn... he will give you another option

Since you have the quest " kill master thief ". you would also have done "kill 3 thieves guild bosses" earlier. thus, it would be hard for you to join thief guild.