Liberation Day
Background
To properly understand the importance of September 14th for both the Risuners of the Central Coast and the City of Ceres, some proper backstory needs to be given.
For centuries, the region around Ceres was one of the prime grounds for the Risuner slave trade. The dominant power in the region, the City of Agra, took tens of thousands from the region and any attempt to build a city or fortification were always futile. They worked together with local chieftans, and made a lot of money from it that built their city into what it is. The term "Agravani" is thus synonymous with slavers regionally amongst the Tupai.
Things however, would change greatly with the arrival of the Kronies in 1115 to the region and the construction of the city of Ceres. To the locals, Ceres was a godsend as it ended the reign of terror that the Argavani had over them. But the Agravani threat did not end with the arrival of the Kronies or the construction of Ceres.
Numerous times over the next 4 years, the Agravani tried over and over to destroy Ceres. Most of their attempts ended in failure against the Kronies, except for one instance of them managing to burn a 1/4 of the city down in 1118. But damned if they were persistence and annoying to the Kronies, and still terrifying to the locals. However, Agra had yet to use its true power, its navy against Ceres and it would be on the 14th of September that the Agravani Fleet under Rukh Shah was sent in force against Ceres.
Battle
News of the Agravani Fleet soon made its way to Ceres and the Tupai panicked. To many of them, this meant certain doom and they wanted out of the city before it happened, but the Kronies weren't about to panic in this situation. Unlike their ill-fated expedition against Agra 5 days later, the Kronies were in a perfect position to utterly annihilate the Agravani. They calmly waited, line astern with their 14 ships as the Agravani closed in before unleashing a maelstrom of fire. The Agravani tried to fire their rockets at the Kronies but failed and soon they fell into panic as the Steam Frigates beared down on them. It was an utter massacre. Out of the 31 ships sent, 26 were lost, including the flagship and Admiral. Agra had never suffered a worse defeat.
Aftermath
Despite mutually offsetting loss at Agra itself 5 days later, the damage had been done to Agra and never again would they ever terrorize the Ailivian coast the way they used to. The fight between them and the Kronies would continue till the end of the protectorate, and despite the Kronies suffering a bad land defeat during their attempts to siege Castra, neither side could claim to be victorious (though they both would.) Today, September 14th is celebrated as Liberation Day by the locals, who proudly carry shackles to their local smith to be destroyed (and then put back together for next year) to symbolize this great day and its meaning.