Help your Alliance in Alliance Wars to receive great rewards. The Alliance receives 5 point(s) for a victory, 1 point for a defeat and 3 points for a draw.
The progress is specific to the Alliance you are currently in. Your rewards are based on the amount of points received from the Wars you have participated in. It is important to note, however, that a player needs to score at least 1 point in the War for their participation to be counted towards the War Chest. 80% or higher participation will give the highest tier of rewards from the chest. 
Please note - if you leave an Alliance and are matched in a War for another Alliance, your personal participation towards the War Chest will be removed.
The accumulated Alliance War Chest points will remain the same because the War Chest progress belongs to the Alliance.
For example, if a new member joins or returns to an Alliance when the Alliance’s War Chest is 20/25, and they participate in a winning War which grants the remaining 5 points, all members of the Alliance gain the War Chest but the new member’s War Chest loot will reflect their participation only from the 1 War.