5e SRD >Gamemastering >Monsters & Foes >Monsters By Type >Constructs >


Forius is an ant-like construct, built by a race of human-sized, sentient (and technologically advanced) ants. Its controllers are seldom motivated to turn their wrath against the surface world, but on the day that they do, Forius will be at their head, and it will prove nigh-unstoppable.

Futuristic Technology. Equipped with plasma lances, a deflector field, and medium-range rocketry, Forius represents technological development far beyond anything known to the surface world… or to the creatures that built it. Its creators found all of its parts in their deep caverns, studied them at length, and assembled the mighty war machine now known as Forius. All of these devices came from another place – or another time.

Engine of War. Forius has only entered full-scale combat on a few occasions, most of which were recorded in surface-dwelling history as earthquakes in regions not normally prone to them. Though its controllers are expansionistic, they use Forius only when a battle is assured to be decisive, as they do not want their enemies to develop strategic responses to it.

Gargantuan construct, neutral

Armor Class 20 (force armor, natural armor)
Hit Points 945 (54d20 + 378)
Speed 60 ft., fly 120 ft.

25 (+7) 12 (+1) 25 (+7) 10 (+0) 11 (+0) 13 (+1)

Saving Throws Constitution+13, Wisdom+6
Skills Insight +6, Intimidation +7, Perception +6
Damage Resistances acid, cold, fire, necrotic, thunder
Damage Immunities poison
Damage Vulnerabilities lightning
Condition Immunities charmed, exhaustion, frightened, petrified, poisoned, stunned
Senses blindsight 300 ft., darkvision 600 ft., passive Perception 16
Languages Common (can’t speak); telepathy 600 ft.
Challenge 20 (25,000 XP)

Special Traits

  • Colossal Creature. Kaiju are creatures far larger than the scale of others. Conventional weapons, even highly-enchanted ones, lack the mass to deal serious wounds to a kaiju. The same is true for all but the mightiest spells. When a creature of Huge size or smaller deals damage to a kaiju with a weapon or feature, or with a spell of 8th level or lower, it deals half damage, which can be reduced further by resistance or saving throws. Siege weapons and creatures with the Siege Monster trait are treated like Gargantuan creatures. Gargantuan creatures and 9th-level spells (including lower-level spells cast with 9th-level slots) deal normal damage, which can be reduced further by resistance or saving throws. Kaiju deal double damage to objects and structures. They ignore normal difficult terrain, and treat thick forests, settlements, or mountains as difficult rather than impassable terrain.
  • Legendary Resistance (3/Day). If Forius fails a saving throw, it can choose to succeed instead.
  • Superior Optics. Forius can see invisible objects or creatures.
  • Deflector Field. Forius projects a force shield that grants it 100 temporary hit points. While the deflector field has any temporary hit points remaining, all ranged attacks against Forius suffer disadvantage. At the start of Forius’s turn, if the deflector field has more than 0 temporary hit points remaining but less than 100, it regains 20 temporary hit points (to a maximum of 100). If reduced to 0 temporary hit points, the deflector field shorts out, coming back online in 1 minute.


  • Multiattack. Forius makes two claw attacks and, if not currently in flight, two wing attacks.
  • Claw. Melee Weapon Attack: +13 to hit, reach 20 ft., one target. Hit: 20 (3d8 + 7) slashing damage, and the target is grappled (escape DC 23). Forius can grapple up to two creatures simultaneously, but not more than one creature with the Colossal Creatures trait.
  • Wing. Melee Weapon Attack: +13 to hit, reach 20 ft., one target. Hit: 20 (2d8 + 7) slashing damage. Forius must be on the ground to attack with a wing.
  • Plasma Lance (recharge 5-6). Forius fires plasma from its stinger in a 120-foot line that is 5 feet wide. Each creature in the area must make a DC 23 Dexterity saving throw, suffering 70 (20d6) fire damage on a failure, or half as much damage on a success.
  • Rocket. Forius fires a rocket at a location within 10 miles. All creatures in a 50-ft. radius must make a DC 23 Dexterity saving throw. On a failure, they suffer 42 (12d6) fire damage and 42 (12d6) bludgeoning damage, or half that on a success. Forius holds a maximum of 10 rockets at a time, and replenishes that stock as part of a short or long rest by collecting and processing 20 lb. of scrap metal per rocket.

Legendary Actions

Forius can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature’s turn.

Forius regains spent legendary actions at the start of its turn.

  • Wing. Forius makes one wing attack. Forius must be on the ground to attack with a wing.
  • Recover. Forius regains 75 hit points. Once it uses this ability, it can’t do so again until the end of its next turn. If its deflector field is active, it also regains 50 temporary hit points.
  • Focus Optics. Forius ends an illusion effect within line of sight. If there are multiple ongoing illusion effects, Forius ends the one created with the lowest-level spell slot (when applicable), or chooses randomly.
Section 15: Copyright Notice

Kaiju Codex. © copyright 2015 Steven D. Russell; Authors Elaine Betts and Justin P. Sluder