Board Game Arena

Hi, I can’t find the rules for knights end cities.
I can’t understand why a player can steal a force e knight with the card even when he doesn’t have the level 3 in the blue city. Can someone explain me that or tell me where the complete rules are. Thanks

You can find the rulebook on the website of Catan, see https://www.catan.com/cities-knights.

On your question: The card "Treason" allows you to steal a mighty knight (level 3) even if you do not have built that level of city improvement. See page 16 of the rulebook.