First of all, it's a bit weird because the battle type may not be what was set originally: Surprise is converted to initiative if the battler placement is "manual" or there is only 1 actor in the party. Pincers is converted to back if the battler placement is "manual" or there is only 1 enemy in the monster group. (Including the different effects on calculations explained below!)
It affects the placement of the battlers of course (position and mirroring).
- If initiative battle or surprise battle (same as if "first strike" flag is set): Escaping via fight/auto/run menu possible during first turn; "Caught the enemy off-guard" message displayed at battle start
- If surprise battle: Enemies attempting to escape always fail (their escape action is converted to a "do nothing" action when executed)
- If pincers battle: Escaping via battle command not possible
Miss probability of physical attacks (probably only from heroes!) is increased by 25 percent points (e.g. 20%->45% - not x1.25!) if...
- Normal or initiative battle: If defender's row is "back"
- Back battle: If defender's row is "front"
- Surprise battle: Always
- Pincers battle: Never
- Normal battle: 50%, or if "first stike" flag enabled then 0%
- Initiative battle: 0%
- Back battle: 100%
- Surprise battle: 0%
- Pincers battle: 100%
- Normal battle: 50%, or if either the "first strike" flag enabled or a "first strike" weapon equipped then 100%
- Initiative battle: 100%
- Back battle: 0%
- Surprise battle: 100%
- Pincers battle: 0%
Base damage of physical attacks is multiplied by 125% if...
- Normal or initiative battle: If attacker's row is "front"
- Back battle: If attacker's row is "back"
- Surprise battle: Always
- Pincers battle: Never
(in the middle, attributes are applied)
Final damage of physical attacks is multiplied by 75% if...
- Normal or initiative battle: If defender's row is "back"
- Back battle: If defender's row is "front"
- Surprise battle: Always
- Pincers battle: Never
There is a number of strange things with this system and things which I'm not entirely sure about:
- As mentioned at the beginning, the "manual placement" setting in the "Battle" tab of the database seems to completely disable surprise and pincers, converting them to initiative and back, which has different effects on damage and miss probability calculations. The same happens if there is only one party member (surprise) or enemy (pincers).
- For all intents and purposes, the "first strike" flags seems to do the same as an initiative battle.
- It appears to me that the miss probability is modified only for attacks from heroes, I think they forgot this in the enemy attack handler!
- Monsters are always in the "front" row. This means that heroes have a further disadvantage during a back battle as their miss probability is always increased and their damage always decreased.
- It appears not very logical to me how surprise and pincers are handled when it comes to calculations... the row and whether a battler is a hero or a monster seem not to make any difference, so for the damage calculation that means that pincers will never do any multipliers and suprise will effectively multiply all basic attacks' damage by 93.75% (125%*75% - I believe attribute modifiers are only multiplicative so they shouldn't effect how the 125% and 75% modifier play together, but I'm not totally sure). It just doesn't make sense to me!