Rift Herald

Defenses

Saving Throws: Strength +8, Constitution +8

Damage resistance: simple physical damage and disruptive damage

Damage immunity: poison damage

Damage vulnerability: acid damage and lunar damage

Immunity to conditions: Frightened, Charmed, Taunted, Paralyzed

Characteristics

Adaptability. Upon scoring a critical hit, reducing a creature to 0 hit points, or receiving a critical hit, the Rift Herald gains 1 adaptability token that can be spent on an Adaptation action.

Adaptation: Stacking. The Rift Herald can spend 1 Adaptation token and an action at the start of its turn to alter its physical form and grow stronger. The Rift Herald must concentrate on the adaptation until the start of its next turn, losing the adaptation if it takes damage, moves, or makes an attack. Stacks can be acquired more than once, growing stronger each time they're acquired. When using this type of adaptation, the Rift Herald must choose one of the options below:

Stack — Mass Accumulation. The Rift Herald increases by one size category, increasing its hit dice by one category and gaining 3 additional hit points for each stack. If it reaches Gargantuan size, the size increase grants an additional hit die and increases the Rift Herald's AC by 1.

Stack — Bio-Built Cascade. The Rift Herald expels an acidic substance from its body, dealing 1 additional Acid damage on all its melee attacks, increased by 1 for each stack.

Stack — Hyperventilated Lungs. The creature is capable of emitting a sonic blast in a 5-foot cone from the Rift Herald; all creatures in the area must succeed on a DC 16 Constitution saving throw or take 19 (3d12) Thunder damage and become Deafened until the start of the Rift Herald's next turn. When acquired again, each additional stack increases the cone's range by 5 feet and the saving throw DC by 1.

Void Infusion. The Rift Herald's attack rolls deal an additional 6 (1d12) Disruptive damage, reducing its maximum hit points by an amount equal to the damage dealt.

Siege Monster. The Rift Herald deals double damage to objects and structures.

Herald's Eye. The Rift Herald has a large purple eye on its back as a weak point; it has AC 12 and 1 HP, only takes damage from melee or ranged attack rolls, and isn't affected by DR. While the Eye isn't destroyed, the Rift Herald has immunity to all damage types other than Gravitational or Cronal.

Attacks

Fury of the Rift (Reaction). When the Herald's Eye is destroyed or the Rift Herald takes 50 or more damage from a single source, it can use its reaction to make an attack roll in a 15-foot cone in front of it; all creatures in the area with AC equal to or lower than the attack roll take 24 (3d12+5) Bludgeoning damage.

Giant Pincer. Melee Natural Weapon Attack, +8 to hit, 10 ft. reach, one target. On a hit, deals 18 (2d12+5) Incisive damage + 3 (1d6) Disruptive damage.

Trampling Charge (Recharge 4-6). The Rift Herald enters a violent frenzy, advancing in a 15-foot-wide line for 45 feet and stopping at the end of the advance; all creatures in the area must succeed on a DC 16 Dexterity saving throw or take 42 (7d12) Bludgeoning damage and fall Prone. On a success, creatures take half the damage and don't suffer the Prone condition. Any structures in the charge's path are immediately destroyed if reduced to 0 hit points; the charge can stop prematurely if the Rift Herald collides with a Huge or larger structure that isn't destroyed by the charge.

Epic Actions

The Rift Herald has 3 charges of Epic Actions, and can spend one of these charges to act. Only one action can be used at a time, at the end of another creature's turn. At the start of the Rift Herald's turn, the number of charges returns to 3.

The Rift Herald can take an action and restore its reaction (if spent).

The Rift Herald can spend all or the rest of its movement.

The Rift Herald can repeat a Saving Throw against an effect affecting it:

Cost. When the Rift Herald repeats its saving throw this way, it loses 7 hit points.

Push. The Rift Herald makes a melee attack against the target's AC. If successful, it can choose between the options below:

Knocking the target down, leaving it with the Prone condition.

Pushing the target 10 feet away from the Rift Herald.