Little known fact - a crystal +5 greatsword combined with the leo ring has the highest counter damage in the whole game. The weapon's stab attack does ridiculous amounts of damage when it interrupts an enemy attack, and is fairly fast and easy to execute.
For full potential, enter hypermode with power within, if you can't kill the enemy that fast I would switch red tearstone out for something like RoFaP or havels if you want better armor and more vitality.
