Evil Spirits
You fight it in Inside North Cave, during Evil Spirits.
Its Nexomon's levels are rolled when the battle starts, from the story's difficulty plus this battle's own weight of 4, as the Battles page explains.
As a tamer battle, it has no capture option.
What its boss cores do:
- A boss vitality core (50): 50% more max HP.
On the map
- Battle
Party
Same for all 6: Cores:Boss vitality core (50)
 Florozard |  Plant | — |
 Blizstrong |  Mineral | — |
 Divette |  Psychic | — |
 Rapnux |  Normal | — |
 Hyphoon |  Wind | — |
 Monkapow | Normal | Plasma, Plasma Cannon, Plasma Star |
History
Changes to this battle across game updates.