Parry

You can simply counter/parry any enemies attack by pressing the normal attack button while moving backward at the right moment an enemy is about to hit you. If you succeed, the enemy will slide back and will be staggered.

Power Attack Combos/Followup Attacks

In Nolvus Awakening, you can chain your power attacks as described here but you can also do some follow up power attacks.

To do a follow up attack combo, press the power attack button while moving backward and when an enemy has been hit, press the power attack button again (this time without direction) and your character will jump on the enemy to do an other powerfull attack when he is on the ground

You can continue to press the power attack button to continue to chain attacks until you don't have enough stamina.