Final Fantasy XII (12) is SquareEnix's 2006 addition to the long running Final Fantasy role playing series. It shares some elements (such as tropes and terminology) with other games in the Final Fantasy series, but it is not a direct sequel.
FF XII uses a "gambit" combat system, where characters can be programmed to take certain actions when specific conditions are met. For example, cast fire on fire-weak enemies, heal if below 50% HP, or cast antidote if poisoned. These gambits can also be prioritized, so that for example, a character of dangerously low health will heal himself before attacking the enemy or casting buffs.
FF XII introduces the characters Vaan, Ashe, Basch, Balthier, Fran and Penelo. FF XII also has avoidable on-field enemies rather than the random encounters of previous games in the series.
Any questions about the gameplay, tactics, or plot of Final Fantasy XII should have this tag.