Need help creating a rogue

[ShubNiggurath]

Okay. That is...not what I want. I want a highly optimized bloke (my party won't be fighting together. Each member is a separate 'boss' for each arc) that will make their lives a living hell while they are dealing with him, but not to outright kill them. I may allow 1 or 2 deaths tho, since we have a cleric and a true necromancer.

That's up to you. It depends on how you play him. Have the rogue find a scroll of arcane sight, just in case.
Also you can always hide from him or run away. He is not that lethal... just impossible to find

"OMG something just stabbed me again! and I lost almost half of my hp!"

[Noliar]

I'd have the adventure give clues as to what they're up against - eg that they have an enemy that is really good at invisibility - so that they can prepare a bit if they take the hint.

[awaken_D_M_golem]

Human Feat Rogue 1 / Wizard 14, Able Learner feat.
It's a standard build.
Can give the Rogue fits.

[ksbsnowowl]

Human Feat Rogue 1 / Wizard 14, Able Learner feat.
It's a standard build.
Can give the Rogue fits.

At least go into Unseen Seer.