Celebrated in Arcadia to give thanks to the Balance and the Guardian for keeping them safe. With this celebration the people are supporting the Balance. If their devotion to the Balance falters, or if they lose their fate in the Guardian, then they are inviting Chaos to destroy them.
The feast normally lasts for three whole days (and nights) every year at the end of July, and everyone celebrates openly. But when April speaks with Benrime Salmin about the Feast of the Balance, she tells April that there is great concern about the Vanguard and their supporters. That is why this year the Feast of the Balance is celebrated for one night only - on the 30th of July - and inside, behind closed doors, because people fear to show support for the Balance under the scrutiny of the growing Vanguard contingent.