Instructions
Purchase as many healing items as you can afford. Once you enter the fight with the Tower Knight, you cannot stop or go back until one of you has defeated the other. Press Up to equip your healing item and press Square to use it.
Equip your strongest weapon and armor. Again, you cannot leave once the fight has begun, so it will serve you well to start with the best equipment.
Head up either of the two staircases and defeat all of the archers on the wall. In such large numbers, the archers can take you down quicker than the Tower Knight can.
Attack the Tower Knight. If you are a melee class, sprint behind him and slash his heels. Keep circling around the Tower Knight so that you are always behind him. If you are a range class, stay up on the walls and shoot spells or arrows at the Tower Knight's head.
Avoid the Tower Knight's attacks. Melee users will need to avoid his back step and leap back. Range users must hide behind the walls on the archway when he stabs at you with his giant spear.
Repeat Steps 4 and 5 until the Tower Knight falls.