What Chris (modiphius) said, but I thought I should weigh in, as the guy running the rules side of things:
More accurately, the situation is this:
A player character rolls 2d20 for a test normally. If he wants to roll more - push his luck, be more daring, etc - he may buy up to three additional d20s for that test, by handing the GM one Threat for each d20 bought.
The GM also gains Threat when the players suffer complications from rolling natural 20s and 'buy them off' (the system is roll low, on a per-die basis - you're counting successes with each die generating up to two successes, so roll-low is faster than roll-high in this instance), when player characters attempt Response Actions (dodge, parry, etc), and under a few other circumstances ("this monster is particularly vile and mighty, so it adds 1 to Threat just by turning up", "the sorcerer's ritual adds one to Threat each round until he's got enough to cast his spell", etc)
The GM can use Threat for minor scene editing ("more guards arrive, drawn by the sound of fighting", etc), or for boosting his NPCs (buying extra dice, Response Actions, buying off complications, and triggering unique special abilities), by paying points out of his pool.
It's "prone to bad GMing" in the same way that any game system is - player behaviour is the kind of thing that should normally be handled through talking it through like adults and/or finding a system that suits your style of play better. No system will suit every player or every group.
If one player is generating all the Threat, then the GM is entirely within his rights to focus his uses of Threat on that one player in return: the towering, brash hero drawing all the attention. I'd still make sure that everyone is on the same page in terms of what they want out of the game, though.
What happens is this: Player is allowed to throw more dice when making a task. The more successes he has, the better he does on the task. But, there is a chance the he rolls bad enough to add points to the Threat Pool, too.
The Threat Pool grows, for the group. It is suggested that buttons are placed into a jar. The GameMaster can spend the points in the Threat Pool to add extra obstacles to the party or a player, whenever he wants.
So, in effect, Conan could build up the Threat Pool single handed, and Subotai could pay for it with a complication he encounters in a completely unrelated part of the adventure.
More accurately, the situation is this:
A player character rolls 2d20 for a test normally. If he wants to roll more - push his luck, be more daring, etc - he may buy up to three additional d20s for that test, by handing the GM one Threat for each d20 bought.
The GM also gains Threat when the players suffer complications from rolling natural 20s and 'buy them off' (the system is roll low, on a per-die basis - you're counting successes with each die generating up to two successes, so roll-low is faster than roll-high in this instance), when player characters attempt Response Actions (dodge, parry, etc), and under a few other circumstances ("this monster is particularly vile and mighty, so it adds 1 to Threat just by turning up", "the sorcerer's ritual adds one to Threat each round until he's got enough to cast his spell", etc)
The GM can use Threat for minor scene editing ("more guards arrive, drawn by the sound of fighting", etc), or for boosting his NPCs (buying extra dice, Response Actions, buying off complications, and triggering unique special abilities), by paying points out of his pool.
The GM is welcome to play up or play down the 'scene editing' uses of Threat as he or she wishes - some GMs may wish to do impromptu retcons like this, others may not feel comfortable doing it, and instead save their threat for things like NPCs dodging or fighting harder. A lot of the time, I'll have a handful of Threat spends lined up in a scene in advance, to represent extant perils that aren't happening constantly. The limiting factor on those events is that there's a limited amount of Threat available at any one time, and it's limited by the players. There are ways for the GM to generate Threat by himself, sure - NPCs can pay excess successes (Momentum) into Threat in the same way that PCs can save Momentum into a group pool - but the players are the main contributors, so they can collectively serve to set the pace of the game by choosing how much Threat they're willing to throw at the GM.So the system is prone to bad GMing? If your Subtai tries to open a lock later on and this lock suddenly has a poison needle payed by from the increased threat pool, I'd agree with you. But in the context of a single scene the mechanism makes sense to me.
It's "prone to bad GMing" in the same way that any game system is - player behaviour is the kind of thing that should normally be handled through talking it through like adults and/or finding a system that suits your style of play better. No system will suit every player or every group.
If one player is generating all the Threat, then the GM is entirely within his rights to focus his uses of Threat on that one player in return: the towering, brash hero drawing all the attention. I'd still make sure that everyone is on the same page in terms of what they want out of the game, though.