Island Oni

Greater Darkvision — A creature with greater darkvision can see perfectly well in areas of darkness and dim light, though such vision is in black and white only. A creature with greater darkvision can see through even forms of magical darkness.

Mist Vision — The island oni ignores the Concealed condition from fog and mist.

Constant Spells — A constant spell affects the monster without the monster needing to cast it, and its duration is unlimited. If a constant spell gets counteracted, the monster can reactivate it by spending the normal spellcasting actions the spell requires.

+1 Status to All Saves vs. Water —

Bean Panic — Oni are curiously afraid of beans, especially as the seasons begin to change. If a creature Interacts to throw a handful of beans at the oni, the oni becomes Frightened 2. While frightened this way, their weakness to spirit damage is increased by 5. The oni then becomes immune to bean panic for 24 hours.

Lost Oni Island (aura, primal) — An island oni can claim an island of up to 1-mile radius in a process that takes 1 week, during which the oni must defeat any who come to challenge its claim. If successful, the oni can freely control the weather on its island and in a 1-mile radius from the shore, with the effect of a successful Control Weather ritual.

This altered weather surrounds the island in thick fog, seaborne mirages, or other phenomena that increase the DC of checks to locate and navigate to the island (Such as Sailing Lore or Survival) to 40, though the oni can allow allies to pass freely. If the oni dies or leaves the island, the weather returns to normal immediately.

Reactive Strike —

Change Shape (concentrate, polymorph) — The island oni can take on the appearance of any Medium or Large humanoid creature. This doesn't change their Speed or their attack and damage bonuses with their Strikes but might change the damage type their Strikes deal (typically to bludgeoning).

The monster changes its shape indefinitely. It can use this action again to return to its natural shape or adopt a new shape. Unless otherwise noted, a monster cannot use Change Shape to appear as a specific individual. Using Change Shape counts as creating a disguise for the Impersonate use of Deception. The monster's transformation automatically defeats Perception DCs to determine whether the creature is a member of the ancestry or creature type into which it transformed, and it gains a +4 status bonus to its Deception DC to prevent others from seeing through its disguise. Change Shape abilities specify what shapes the monster can adopt. The monster doesn't gain any special abilities of the new shape, only its physical form. For example, in each shape, it replaces its normal Speeds and Strikes, and might potentially change its senses or size. Any changes are listed in its stat block.

Conductive Downpour (electricity, primal, water) — The island oni fires a bolt of lightning into the air, which immediately roils with dark clouds. Rain falls in a 60-foot emanation{60-foot radius emanation}, centered on the oni, for 1 minute, filling the air and pooling on the ground.

Creatures in the aura gain weakness 10 to electricity, and the entire area is greater difficult terrain for Flying creatures, and difficult terrain for creatures on the ground or Climbing, unless they also have a swim Speed.

Electrifying Pierce (electricity, primal) — The island oni doesn't need to use additional actions to keep the creature grabbed; the creature remains grabbed as long as it's impaled. The grabbed creature can attempt to Escape as normal. The island oni can only have one creature impaled this way at a time.

Swallow Whole (attack) — Medium, 3d8+10 bludgeoning, Rupture 30

The monster attempts to swallow a creature of the listed size or smaller that it has grabbed or restrained in its jaws or mouth. If a swallowed creature is of the maximum size listed, the monster can't use Swallow Whole again. If the creature is smaller than the maximum, the monster can usually swallow more creatures; the GM determines the maximum. The monster attempts an Athletics check opposed by the grabbed creature's Reflex DC. If it succeeds, it swallows the creature. The monster's mouth or jaws no longer grab a creature it has swallowed, so the monster is free to use them to Strike or Grab once again. The monster can't attack creatures it has swallowed.

A swallowed creature is Grabbed, is Slowed 1, and has to hold its breath or start suffocating. The swallowed creature takes the listed amount of damage when first swallowed and at the end of each of its turns while it's swallowed. If the victim Escapes this ability's grabbed condition, it exits through the monster's mouth. This frees any other creature grabbed in the monster's mouth or jaws. A swallowed creature can attack the monster that has swallowed it, but only with unarmed attacks or with weapons of light Bulk or less. The swallowing creature is Off-Guard against the attack. If the monster takes piercing or slashing damage equaling or exceeding the listed Rupture value from a single attack or spell, the swallowed creature cuts itself free. A creature that gets free by either Escaping or cutting itself free can immediately breathe and exits the swallowing monster's space.

Effect: Engulf and Swallow Whole

If the monster dies, a swallowed creature can be freed by creatures adjacent to the corpse if they spend a combined total of 3 actions cutting the monster open with a weapon or unarmed attack that deals piercing or slashing damage.

Tripping Tide (water) — The island oni sweeps their spear in a full circle, releasing waves of seawater. All creatures in a 20-foot emanation must succeed a DC 37 Reflex saving throw or fall Prone.

Improved Grab —