Anyone familiar with the Apocalypse World series of games will have no trouble picking up the basic mechanics of Libreté: PCs attempting to affect the world roll 2d6 and add relevant bonuses, trying to score above or within a range of numbers. This is a simple, elegant system suited for games that emphasize narration–a natural choice for Libreté. However, the game has been modified slightly to allow for new mechanics that expand and alter this main system, such as Bile. As Vivien writes:
…Bile symbolizes stress and malaise, a representation of the void that inhabits all lost children. It’s secreted by unhappy, suffering kids giving them the strength to triumph over obstacles while pushing them toward antagonism. Those failing to sublimate it through violence eventually corrupt and become withdrawn.
Reflecting this, each time their character is confronted with a stressful situation, a player has the opportunity to draw 1-3 Bile tokens from the reserve—it’s that simple. It may happen in the middle of a conversation, in response to some hurtful remark, responding to another PC’s or the Advercity’s childity, experiencing pure loneliness and even in retrospect, because a player forgot to take a token at the time. Taking Bile isn’t always accompanied by visible effects—it’s primarily a manifestation of an internal phenomenon.
Example: after lashing out at a sirain, Louve sees horror in the eyes of someone she loves. The player takes two Bile tokens from the reserve reflecting her character’s emotional state.
Advercity, your role here is regularly reminding everyone of this central rule and sometimes questioning players about their characters’ feelings but not to judge their decisions. Each player alone decides whether their character “gains” Bile. If they can explain their choices, they’re not obligated to do so and you mustn’t criticize them. Some players take handfuls of tokens, others are more circumspect, this is their choice and doesn’t “break” the game.
Accumulating Bile has a positive purpose: PCs can choose to apply Bile to a task roll (called “childities” here), adding the number to the result. When you’re really trying to hit that 7+, getting +3 to your 2d6 is a tempting offer.
Some things became apparent to me as I read this. The tradition of “failing forward” has been moved up in the pecking order–now, children run the risk of succeeding too much. For most childities, the ideal roll is somewhere between 8 and 10: anything less is a flat failure, but anything more means that you get what you want at the expense of you or another’s safety and well-being. You get to gamble on this by using your accumulated stress to push yourself beyond what’s healthy–consider the similar stress mechanic in Darkest Dungeon.
As well, Bile forces characters in Libreté to recognize trauma as an actual force of play. As Bile builds up, PCs must either expend it in healthy ways–relaxation, entertainment, or other forms of self-actualization–or harness it for childities in times of trouble. A child who gains Bile but never expends it has a chance of EXPLODING and doing something truly foolish or dangerous. It is not enough for your players to be comfortable with their actions and the world around them. They must ensure their children are too.