Nivalis
You fight it in Ice Cave Battle Room.
Its Nexomon's levels are rolled when the battle starts, from the story's difficulty plus this battle's own weight of 3, as the Battles page explains.
It's a wild battle, but it doesn't allow capturing, so the capture option never shows. Its Nexomon's levels are hidden during the battle.
Winning it gives ×5 EXP and ×5 coins.
Its data gives its Nexomon HP ×1.45 and stamina ×1.45, but this build never applies that: the game only uses these modifiers behind a switch it leaves off.
What its boss cores do:
- A boss vitality core (250): 250% more max HP.
- A boss stamina core (300): 300% more max stamina.
Party
 Nivalis |  Water | Hydro Sphere, Freeze, Water Blast, Bubble Attack | Boss vitality core (250), Boss stamina core (300), Destruction Core (II), Vitality Core (III) |
History
Changes to this battle across game updates.
- Coins multiplier changed from — to ×5
- EXP multiplier changed from — to ×5
- Party
- −Nivalis · Water · Hydro Sphere, Freeze, Water Blast, Bubble Attack · Boss vitality core (150), Boss stamina core (300)
- +Nivalis · Water · Hydro Sphere, Freeze, Water Blast, Bubble Attack · Boss vitality core (250), Boss stamina core (300), Destruction Core (II), Vitality Core (III)
- Party