Posalon is a worldbuilding server where players make nations and build a shared lore story together. It has been running for over 3 months and it has an active community.
The server supports both Java and Bedrock so more people can join in. The big feature is Movecraft which lets players build ships tanks and planes out of blocks.
There are also extra plugins like Brewery X plus lands for claiming and a market with an auction house. It even has a stock market and guns and sea zones. It is not only about military stuff though since the main focus is community worldbuilding and making history with other nations.
