My go to SL 125 Knight build start as a solider for PVP SL 125. Very tanky and beefy knight, I always use the flute armour because its just the best armour in the game, for me of course. I always use water veil to cancel out insta-kill fire moves. With 87% damage reduction there's no need to worry. For magic I suggest using all your hp to learn how to dodge all magic attack. Use regeneration for poisons and plague if you get caught. I like using the Fragrant ring and dual wield crescent rapier giving me 2 mana regen/sec for 60 second which is enough to use regeneration again when it runs out. That's all have fun.