Approaching monsters in dungeons start encounters. Depending on the player's approach, the encounter will either be Threat, Side, or Pre-Emptive.
Approach enemies from the front to initiate a Threat Encounter. In Threat Encounters, the ATB Charge will be low and the Momentum Charge will be empty at the start of the battle.
Approach from the side and enter battle to initiate a Side Encounter. In Side Encounters, the ATB and Momentum Charge will be around half full at the start of the battle.
Approach from the rear and enter battle to initiate a Pre-Emptive Encounter. In Pre-Emptive Encounters, the ATB will be full and you will have 1 MC at the start of the battle.