This fork uses a Cosmos-SDK chain to add betting mechanisms. The winner of the duel will receive the winnings of the other. Using https://github.com/Reecepbcups/cosmos-minecraft-integration
Public Duels plugin on Spigot (without CosmosSDK integration work): https://www.spigotmc.org/resources/multiarena-duels-1v1.44820/
All credit to the original author Dartanman for the duel's logic, kits, and arena work.