Receiving damage in Dragon Age II results in one of the four possible outcomes depending on the amount of force behind it. Force is calculated as:
Force of the attack = (Damage * Force Multiplier) - Fortitude
The amount of damage done (after taking into account armor/resistance and damage reduction) is multiplied by the force multiplier of the attack, e.g. 10dmg*x3-multiplier = 30 force. Fortitude (force resistance) is subtracted from the amount of force that is received, e.g. 10 fortitude = 30-10 = 20 force taken.
Depending on the amount of force taken relative to max health you get:
- <10% of max health = twitch of head, no interruption of actions
- <20% of max health = knocked back a step, interrupted actions
- <30% of max health = knocked back several steps, interrupted actions
- >30% of max health = knocked down/sent flying, interrupted actions
Based on this there are several methods to reduce knockback issues.
- Increase armor rating/damage resistance = less damage taken
- Increasing fortitude = less force taken
- Increasing constitution = less force taken relative to max health
- Items with immunity to knockback properties = immune to knockback (2 and 3) but knockdown (4) still possible
- Not getting hit via dodging (via moving away or defense) or not being targeted (threat management and crowd control)
After some experience and gaining greater crowd control ability it is possible to get by quite easily via the methods listed above. However, for the initial levels while constitution, fortitude, and armor/damage resistance are low knockback issues will be a major problem unless you are very good at the last option.