A Fossil Battle is the battling system of Fossil Fighters. In a Fossil Battle, each side can use anywhere from one to three Vivosaurs, placed in Attack and Support Zones. Each side has four Zones: one Attack Zone (AZ) that must be occupied at all times, two Support Zones (SZ) occupied by
the second and third Vivosaurs at the beginning of the battle, and an Escape Zone (EZ) that cannot be occupied until an SZ Vivosaur is switched to the AZ position, at which point the AZ Vivosaur will retreat to the EZ.
Vivosaurs in the Attack Zone deal more damage and can attack both the enemy AZ and the enemy SZ, but will also come under fire from all three enemy positions and takes more damage than Vivosaurs in the SZ.
A Vivosaur in the SZ will take less damage than one in the AZ, but will also have its Attack power reduced (with some exceptions). However, SZ positions can apply Support Effects to either their own or the enemy AZ which can either increase or lower stats (but not LP). It should be noted that some Vivosaurs reduce their allies' stats or increase the enemy's stats and may be better utilized in the AZ. However, support effects are not universal, as some Vivosaurs lack them entirely. A Vivosaur in the SZ can only attack enemy Vivosaurs in the AZ position (not including Team Skills).
The Escape Zone causes Vivosaurs placed in it to be unattackable (even by the few skills that hit both AZ and SZ) but also does not allow EZ Vivosaurs to attack. Vivosaurs in the EZ will not apply support effects and have no effect on the battle until they return to an SZ two turns later. A Vivosaur can end up in the EZ if an SZ Vivosaur is swapped with the AZ Vivosaur, or the AZ Vivosaur is knocked there.
If a Vivosaur is forced into the EZ by a Knock skill, it will return to the SZ only one turn later, instead of two. Vivosaurs cannot be placed into the EZ until after the battle has started.
In Fossil Fighters Champions, there is no EZ. This battle system is replaced with zone rotation.
Similarities to other games
The multi-zone, support-affected battle system is reminiscent of Digimon World Dawn and Digimon World Dusk , where there are five zones and Digimon in adjacent zones increase some of their allies' stats.