The Natarian Knight is the most skillful and fierce type of warrior. Although having a legendary anti-infantry defense, the Natarian Knight's anti-cavalry defense is surprisingly lower than usual. Their attack power is slightly lower than Roman Equites Caesaris also. Natarian Knights, like all Natarian units, are controlled by NPCs , and players can not train or fight with them. For travian advice go here
"Only the most skilful and strongest warriors of the Natars survive the training to become a Natarian Knight. Seeing them fight fills one with awe and shows what true warfare is. They wield their blades as if they were one with their arms and hands and use their shields seemingly as a natural extension of their bodies. Even the horses they ride are specially bred and trained - no normal horse would be able to wear the armour the knights' horses wear, let alone the knight himself, and still be able to go to war. Whispers of their glory have even reached the most distant kingdoms, spreading fear and horror."
-Travian FAQ