Server Plugins
It is possible to write plugins in C# and use these from Lua.
These plugins must implement a certain Interface to be usable.
In the moment there is no extensive written documentation, but there exists a tutorial plugin which is well commented and which can be used as a starting point.
CAVEAT: Server plugins are officially not supported and you can seriously shoot yourself in the foot with them. You need to know what you are doing to really use them.
Compiled plugins need to be placed into
\build\base\plugins
If you use LuaTableProxy types to return Lua tables your plugin also must be linked against Shardsserver.exe, which means you probably have to update it a lot.
Tutorial Download Link:
https://www.legendsofaria.com/downloads/u3d2bdea/LoA_TutorialPlugin.zip