For those having problems with the game asking for the serial key - WarswordConquestTeam/Warsword-Conquest GitHub Wiki

FOR THOSE HAVING PROBLEMS WITH THE GAME ASKING FOR THE SERIAL KEY

"steam key converter: https://www.taleworlds.com/en/Account/ConvertSerial"

"So after it kicked me out of the game for reaching level 8, I went and looked up my serial key on GOG and entered it in. The GOG key worked first try, so no need to convert like with the Steam keys. GOG key is a menu option from the drop-down menu on the game page in your GOG library if any of you other GOG people are having key trouble and don't know where to look."

This is caused by a bug known to TW but never corrected:

"Message for Daegoth, dveloper of Taleworlds:

Hello everyone,

As some of you know, during a certain period of time, Steam provided you 5x5 keys instead of 4x4 keys. People who bought their game during that time, received those 5x5 keys. The disadvantage of those keys is that with those, you won't be able to install and play the game without Steam. In order to provide a solution, we allowed people who has those faulty keys to receive a 4x4 key from our web site. All you need to do is to register your serial key to Taleworlds site and it will automatically provide you a 4x4 key.

(the serial key converter above)

UPDATE #2: I've been getting too many messages regarding the converter. Please be informed that this converter was made only for a bunch of serial keys that were given from Steam in a different format. For people who have bought the game in 2011, this converter doesn't have any functionality. If you want to convert your 5x5 Steam key to 4x4 Taleworlds key, then you just have to right click on your game and select "View game CD key". That's all. You can use that key for playing Mount&Blade; series without Steam."

We can't do anything about it.