Eador. Imperium is the name of the latest expansion. The add-on is a stand-alone version of the game that is currently on Steam's Early Access. Eador. Imperium's prices range from 11$ to 18$ depending on the region, discount, and whether you have Eador: Masters of the Broken World or not.
The developer, Snowbird Games, has added 4 new heroes, 15 new units, new winter Shard world, and new tactical map to the game. You can read more details about the game on the official website.
To celebrate the Early Access start, Snowbird has released this Early Access trailer: