Here’s my take on what might be the largest battle of this AU so far, the invasion of Ravenna.
After the collapse of Fort Talos and the fall of the other island allied to Ravenna like Shell Island and Frostmill, all available vessels would be recalled to the home island as the Ravenneans prepared to defend their homeland. The entire island was fortified, with cannon and mortar emplacements set up to fire on any Atlantean ship that approached.
When the Atlanteans finally did show up, they did with hundreds of vessels, the largest concentration seen anywhere in the Bronze Sea. The fighting lasted for weeks, but while the Ravenneans held the home-field advantage, the sheer overwhelming numbers of the Atlanteans followed by even more coming in meant that the Ravenneans were slowly but surely losing ground.
Tiberia was the first to fall, followed by Rasna as the hordes closed in on the walls of Rubica. As it soon became clear that the battle was lost, King Calvus ordered the remaining civilians into Mount Caesar as he personally led the final charge. Though he claimed a great swathe of Atlantean lives that day, he was eventaually struck down and wounded, forced to evacuate as the Atlanteans overran Rubica.
With the fall of Rubica, the remainder of the Ravenna Navy fled to Mount Othrys with as many people as they could save, chased by Atlanteans the whole way. Those who managed to make it into Mount Caesar are now led by Revon and Julian, the former directing the remains of Ravenna’s army while the latter seeks to find a way to cure his brother whose mutations have been coming on slower thanks to his Aether Magic.
It’s even been rumored by survivors that Revon’s secretly been leaving Mount Caesar in short trips to find ingredients for a potion to cure Calvus. Some have even suggested that he’s been luring unsuspecting people in to test his potions on them. Of course, that’s just a rumor… right?