Alliances form a major cornerstone of diplomacy between kingdoms, and allow various kingdoms to aid one other in return for receiving the same treatment from their allies. When joining an alliance you may choose to open negotiations with anyone they are allied with to form an alliance on your turn, if the faction is an NPC Kingdom gain +2 to the Negotiation check with no chance of critical failure.
Alliances are simple with very few rules attached to how they work.
There are two ways to garner allies. Negotiations, and through payment.
Negotiating with another kingdom to become allies requires a Negotiation check. Kingdoms that are more than 6 squares away from your nearest border impose a -1 penalty your Negotiation check. Every additional 2 squares away imposes another -1 penalty.
Success means you and the target kingdom forge an alliance. This alliance lasts 1 year (12 turns) and adds your Negotiation bonus as additional months to the duration. Failure means you must wait for 4 months before attempting to negotiate an alliance again.
Players need not make a check normally and need only be within 6 squares of each other or send an envoy. An agreed alliance always lasts 1 year or until dissolved whichever comes first, refusal to an alliance requires a Negotiation roll at DC 16 from the one offering the alliance with failure resulting in the below penalty and success preventing the penalty.
Alternatively, an Alliance may be bought. This cannot be used against a kingdom in which you've critically failed your Negotiation check against if this is attempted to be done afterwards. The amount of Wealth necessary to buy a kingdom's alliance is dependent on their size, your Negotiation stat, and the kingdom's distance away.
The amount of Wealth required to buy an alliance is equal to 10 + Kingdom's Size - your Negotiation + distance (see below).
Kingdoms 6 squares away cost an additional 10 Wealth, +1 for every 2 squares beyond 6.
Kingdoms have the right to refuse payed for alliances with no penalty, however refusing an alliance from someone who has attempted to persuade you through Negotiation results in a loss of Prestige equal to the opponent's Negotiation (minimum 1).