Here I've compiled all of the Damage Modifiers for attacks in DX except the individual Scalings of each attack. All of this is based on the idea of adding or subtracting multiples of 10 from a base of 100% (being normal damage without any modifiers). This damage can be amplified with various Status effects, and can be mitigated the same way, or with inherent Scaling. These numbers are all additive to one another, including Combo Scaling. Total damage of a single attack can never be greater than 200% from modifiers, or lower than 10% (or 1 damage, at the very least.)
Attack Up: +20% damage dealt
Attack Down: - 20% damage dealt
Rage (red HP): +20% damage dealt
Synergy Burst: +10% damage dealt
Synergy Up: +20% damage dealt during SB
Synergy Down: - 20% damage dealt during SB
Defense Up: - 20% damage received
Defense Down: +20% damage received
Rage (red HP): - 30% damage received
Synergy Burst: - 10% damage received
Synergy Up: - 20% damage received during SB
Synergy Down: +20% damage received during SB
Critical hits deal 20% more damage, but otherwise are additive as well. However, Critical hits have an extra-strong effect when used with Attack or Defense changes, and move their base values from 20% to 30% and 40% respectively. Landing a Critical Hit increases the damage of the combo by 10%. It is worth noting that only the first hit of any Combo can receive the full 20% from landing a Critical.
Crit = +20%
Crit + AtkUp = +30% + 20% = +50%
Crit + DefDn = +40% + 20% = +60%
Crit + Rage = +20% + 20% = +40%
Crit + Synrgy = +10% + 20% = +30%
Crit + SngUp = +20% + 10% + 20% = +50%
Crit + SngDn = - 20% + 10% + 20% = + 10%
Crit + DefUp = - 40% + 20% = - 20% (Crit has no effect)
Crit + AtkDn = - 30% + 20% = - 10%
Crit + Rage = - 30% + 20% = - 10%
Crit + Syngy = - 10% + 20% = +10%
Crit + SngUp = - 20% - 10% + 20% = -10%
Crit + SngDn = +20% - 10% + 20% = +30%
Once you have your Scaling and Modifiers mathed out, just subtract them to 100 and you'll have your result damage. This can never go below 10%, and cannot go above 200%.
TLDR; here are the scalings for each type of damage modifier:
- Plus or minus 20%. 30% if landing a Critical Hit.
- Plus or minus 20%. 40% if receiving a Critical Hit.
- Deal 20% more damage and take 30% less damage.
- Deal 10% more damage and take 10% less damage.
- Plus or minus 20% while in Synergy Burst.
- 20% more damage to the first hit.
- Dependent on each and every move a character has.