Kaiju for Dungeons and Dragons: Tectonicus, Titan of Earth and Lightning

Back again with another Kaiju for Dungeons and Dragons!  A user on Reddit requested I create a worm-based kaiju for the world of Yamatai, but I wanted to be more original than just “three hundred foot long worm”. My mind drifted back to a creation I made for a kaiju forum RPG years ago: An earth golem with electricity-spitting Mongolian death worms burrowed into it. Enjoy!

Tectonicus, Titan of Earth and Lightning

Colossal monstrosity (kaiju), lawful neutral
clay golem kaiju dungeons and dragons mongolian death worm cryptozoology

Artwork: Clay Golem, Property of Wizards of the Coast

“The myths of the desert death worms were true, we saw them burrowed into that walking mountain.” – Brother Tino’s Chronicle of Greater Kaiju

The deserts of southwest Yamatai were considered a desolate, inhospitable hellhole by most races. In addition to unforgiving heat and bandits, rumors of lightning spitting worms dwelling beneath the sand scared most travelers away. When a series of earthquakes rocked the region, those rumors were proven true when a three hundred fifty feet tall humanoid composed of sand and stone rose from the ground with death worms burrowed into its body: the titan of earth and lightning Tectonicus.

Symbiotic Bond. Tectonicus represents a symbiotic fusion of the sturdiness of stone and the destructive power of lightning. The death worms that dwell within its body can fire blasts of electric energy at Tectonicus’s enemies while gaining protection by burrowing under the earth titan’s rocky hide.

Botched Construct. The first appearance of Tectonicus closely coincided with the disappearance of an apprentice alchemist that traveled into the desert with a Manual of Golems. However, Tectonicus serves no known master and acts of its own accord.

Order of the Desert. Tectonicus enforces a regime of law and order upon the desert region it calls home, though not neccessarily a benevolent one. One of the first targets of Tectonicus’s wrath was a notorious band of thieves headquartered in the desert, but on another occasion it attacked an imperial mining operation. Naturally, this attitude brings Tectonicus into conflict with other kaiju that enter its territory.

Mightiest of the Mighty. Of all known kaiju, Tectonicus displays the greatest physical strength. Some accounts claim its fists can shatter rock structures many times larger than itself.

Reluctant Ally. Affairs outside of its territory rarely concern Tectonicus. It has however been willing to journey outside the desert and fight alongside other kaiju when it is convinced an outside force may threaten its home.

Strange Bedfellows. Tectonicus has displayed a peculiar affinity for the plague kaiju Vermutila, possibly due to the influence of its death worm companions. Tectonicus and Vermutila have stepped in to assist each other on several occasions.


The death worms that have burrowed in the rock and dirt of Tectonicus’s body can manifest with a different elemental attunement. Tectonicus’s Electric Field, Death Worm Thunder, and Lightning Pulse attacks have their damage types changed to any of the following: Acid, Cold, Fire, Necrotic, Poison, Radiant, or Thunder. Additionally, any death worms summoned by Tectonicus have their Lightning Sting attack changed to this damage type. Lastly, Tectonicus and its Death Worm summons replace their lightning damage immunity with this damage type.

  • Armor Class 28 (natural armor)
  • Hit Points 1344 (40d20+544)
  • Speed 120 ft.

35 (+12) 12 (+1) 34 (+12) 16 (+3) 15 (+2) 12 (+1)

  • Saving Throws Wis +12, Cha +9
  • Damage Resistances acid, bludgeoning, fire, thunder, piercing, radiant, and slashing from non-kaiju attacks
  • Damage Immunities cold, lightning, necrotic, poison
  • Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, poisoned
  • Senses darkvision 200 ft., passive Perception 10
  • Challenge 32 (195,000 XP)

Electric Field. At the start of each of Tectonicus’s turns, each non-kaiju creature within 100 feet of it must make a DC 10 Constitution saving throw, taking 11 (2d10) lightning damage on a failed save, or half as much damage on a successful one.

Kaiju Hide. Any time Tectonicus is targeted by a magic missile spell, a line spell, or a spell that requires a ranged attack roll, roll a d6. On a 1 to 5, Tectonicus is unaffected. Additionally, Tectonicus is immune to spells of 6th level or lower. It has advantage on saving throws against all other spells and magical effects.

Massive Combatant. Tectonicus’s weapon attacks can hit all creatures within a 15 foot square. All creatures in the area whose AC is equal to or lower than its attack roll are affected.

Legendary Resistance (3/Day). If Tectonicus fails a saving throw, it can choose to succeed instead.

Siege Monster. Tectonicus deals double damage to objects and structures.

Titanic. Because Tectonicus is so massive, all forms of difficult terrain, except for mountains, don’t hinder its movement. Huge or smaller creatures can move through any squares occupied by Tectonicus, or vice-versa. Creatures that are Large or smaller don’t provoke opportunity attacks from Tectonicus. It is possible for a Huge or smaller creature to climb Tectonicus—this requires a successful DC 20 Strength check.


Multiattack. Tectonicus makes three attacks: two with its fists and one with its slam.

Fist. Melee Weapon Attack: +19 to hit, reach 20 ft., one target. Hit: 42 (5d12 + 12) bludgeoning damage.

Slam. Melee Weapon Attack: +27 to hit, reach 30 ft., one target. Hit: 111 (20d8 + 21) bludgeoning damage and the target must make a DC 34 Strength saving throw, or be knocked prone.

Death Worm Deployment (3/Day). Tectonicus commands 2d6 death worms to enter combat. They emerge from its feet into an adjacent square.

Death Worm Thunder (Recharge 5-6). The death worms burrowed inside Tectonicus fire a high-intensity blast of lightning energy in a 250-foot cone. Each creature in that area must make a DC 20 Dexterity saving throw, taking 81 (18d8) lightning damage on a failed save, or half as much damage on a successful one.


Tectonicus 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. Spent legendary actions are regained at the start of its turn.

Fist Attack. Tectonicus makes a Fist attack.

Slam Attack. Tectonicus makes a Slam attack.

Lightning Pulse (Costs 2 Actions). Tectonicus’s Electric Field intensifies and spreads outward. Each creature within 120 feet of Tectonicus must make a DC 24 Dexterity saving throw, taking 72 (18d8) lightning damage on a failed save, or half as much damage on a successful one.

And now, a stat block for the death worms that dwell inside Tectonicus’s earthen body!


Large monstrosity, unaligned

mongolian death worm kaiju dungeons and dragons dnd homebrew cryptozoology
Artwork: “Mongolian Death Worm – Paranoia” by budhiindra (Deviantart)

  • Armor Class 13 (natural armor)
  • Hit Points 80 (10d10+30)
  • Speed 20 ft., burrow 30 ft.

19 (+4) 10 (+0) 16 (+3) 16 (+3) 5 (-3) 12 (+1)

  • Saving Throws Dex +4, Con +8
  • Damage Immunities lightning
  • Condition Immunities paralyzed
  • Senses darkvision 30 ft., tremorsense 30 ft., passive Perception 7
  • Challenge 6 (2,300 XP)


Multiattack. The death worm makes two attacks: one with its bite and one to constrict.

Bite. Melee Weapon Attack: +7 to hit, reach 10 ft. Hit: 11 (2d6 + 4) piercing damage.

Constrict. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 13 (2d8 + 4) bludgeoning damage, and the target is grappled (escape DC 16). Until this grapple ends, the creature is restrained, and the snake can’t constrict another target.

Lightning Sting (Recharge 5-6). The death worm exhales lightning in a 40-foot line that is 5 feet wide. Each creature in that line must make a DC 14 Dexterity saving throw, taking 28 (8d6) lightning damage on a failed save, or half as much damage on a successful one. The damage of this attack increases by 1d6 for each additional death worm in combat.

Homebrewery link

PDF link

Questions? Comments? Formatting or mechanics suggestions? Let me know! Just leave a comment or contact me. Stay tuned for more Dungeons & Dragons kaiju homebrew content.

Thanks to /r/UnearthedArcana and /r/MonsterADay for formatting and mechanic suggestions.

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