[Gatts]

In Kordar you can get them very very rarely...
Randomly they can be bought all around the world, but often in Demonis, sometimes in Elven Islands, and often in Haas Labyrinth...

But as you will continue on your quest - the main castle of King Mark will be updated... if you are lucky, there will be infinite Knights ... Mostly there are only Horsemen are there nearly always... (later on)... so good luck on getting them. But mostly you will miss them in some game phases...