Beings of Tash Kalar
As most lone riders in the game, Knight has a L-shaped pattern. The Knight is summoned sitting on the back of this L.
Knight rides his horse through the enemies. You may see his limiting condition by two ways - he is too noble and spares lives of those who are weaker... or he is too imperious to fight those who are not worth it. You choose.
Knight is sure one of the strongest Empire beings. So strong, that actually, instead of hints how to use it, I would suggest how to play against it. When facing Empire, and before you saw the Knight, it is not good idea to create long chains of your heroic beings. Especially in "close combat", when your tokens are close or intertwined with enemies, the Knight may change the board balance drastically: by one action, the opponent gets a heroic piece and destroys up to four heroic pieces of yours. Thus when placing a heroic piece, it is always good idea to ask: "What happens if my opponent has a Knight in his hand?"
Knight looks like basic stone of Imperial army. But in fact, it was the last added card to the Empire, and probably last card added to the basic decks. After all factions were created, the number of the cards in each faction settled on 18, and playtesting of these factions started, there was still no Knight. Instead, there was War Priest, with rather complicated pattern and effect that included destroying and converting. We decided Empire needs more straightforward cards, so War Priest was dropped for now, and replaced with Knight - a card based on Wolf Rider (who was called Wolf Knight at that moment), but with one extra movement and one new limitation.