Physical Defence is a stat which reduces the amount of damage received from physical attacks.
Characters' Physical Defence
The damage that characters receive from physical attacks is reduced by the amount of their physical defence. A physical defence of 1,000 will reduce physical attacks by 1,000 points of damage.
If physical defence is greater than or equal to the attack's physical damage, the character will receive only 1 point of damage, or 0 if they block the attack.
Enemies' Physical Defence
Unlike characters, an enemy's physical defence stat is a percentage and has a direction. Physical attacks from that direction will have the damage reduced by the specified percentage. The enemy's physical defence in other directions is zero. Most enemies have a physical defence of zero in all directions, and receive the full amount of damage from physical attacks unless the attack is blocked.
For example, Krabbles have a physical defence of 25 to the rear; if hit from the rear by a physical attack, the amount of damage will be reduced by 25%. Nebulae have a physical defence of 80% in all directions, so physical attacks will do only 20% of the normal amount of damage. One enemy can have a physical defence of 100% in all directions, which reduces the damage of all physical attacks to only 1 point if they do not block the attack.
The Phys Def Down debuff will reduce an enemy's physical defence by the specified amount. If the result is less than zero, the enemy will take extra damage from physical attacks. For example, if a Krabble is hit by a Phys Def Down of 25%, their physical defence will be reduced to 0 for rear attacks, causing them to take full damage from physical attacks to their rear; their physical defence in other directions will be reduced from 0 to -25%, causing them to take an extra 25% damage from physical attacks to their front and sides.
Enemies' Attack Multipliers
Physical Defense reduces damage before a monster's multiplier for special arts is applied.
For example, a Glory Slobos's auto swing damage is 1,434. When it uses the special move Thrust, it multiplies its swing damage by 3.5 to 3.8, meaning its Thrust will hit for somewhere between 5,019 to 5,450. In this example, we will say that the Thrust uses the 3.8 multiplier and therefore hurts for 5,450.
If the Glory Slobos attacks a party member with zero physical defence, it will auto swing for 1,434 damage and Thrust for 5,450 damage.
But if the Glory Slobos were to attack a party member with 1,000 physical defense, it will auto swing for 434 damage and Thrust for 1,650 (which is 434 times 3.8).
Skills and Buffs
Physical Damage received = [(Auto Swing of Monster - P.Def) X Enemy art Multiplier X "Damage Reduction A" X Melia's Summon Earth buffs
- Auto Swing = Normal auto swing of monster
- P.Def = Physical Defense of targeted party member
- Enemy Art Multiplier = Multiplier of Swing Damage to get damag of special art (for example, a Glory Slobos multiplies its swing damage by 3.5 to 3.8 to get its damage for its Thrust special art)
- Damage Reduction A = 100% - all skills (and gems?) added together that reduce physical damage taken. For example Fiora's Physical Resilience skill lowers physical damage taken by 10%, and Dunban's Body of Steel skill lowers damage taken by 15% and a max Physical Protect gem would reduce physical damage by 50% for the first 30 seconds of a battle.
- Melia's Summon Earth Buffs = lowers physical damage taken by 15%, 30% or 45%, which is fifteen percent each application which stacks up to three times.
So if a party member were to have 1000 P.Def, skill linked both Dunban's Body of Steel plus Fiora's Physical Resilience skills, and had all three applications of Melia's Summon Earth buff, they could expect this amount of damage from a Glory Slobos during a Thrust (assuming monster's auto swing is 1434 & multiplier is 3.8)
[(1434 - 1000) * 3.8] * 0.75 * 0.55 = 680