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hexia, mercury dragon

In my current campaign called the Clash of the Titans  – a modified Odyssey of the Dragonlords campaign – the players fought a “green” dragon called Hexia.  The original was just an adult green dragon which my party of 6 to 7 level 12 PCs would eat up.  So I created a modified version.  The entire 4 hour session was spent either preparing to, or actually, fighting the dragon.  Here is my modified Hexia.  Some idosyncries may need to be explained:

  • My Thylea is a science-fantasy setting where bio-mechanical life is common. Hexia is a bio-mechanical dragon.
  • She was upgraded to ancient because by the time my group got around to her she would not have been a challenge otherwise.
  • Though she is purple/orange coloured scales, my PCs had always assumed – until they saw her – she was a green dragon.  So I kept her breath weapon green.  I didn’t keep her a green dragon because heroes feast would trivialise the battle, but I did still want to reward good planning. Hence her split breath weapon.
  • I used the banner picture on this post as the dragon.  So she used technology to fly.
  • I added more interesting terrain effects.
  • I used DCC spells for her spell casting.  The magic-missile in particular had the PCs in fear, as the force damage could outright kill the PCs (and I have no resurrection magic in my world).
  • I use timers for recharges, this timer is public so the PCs know when the next breath weapon is coming.
  • I actually used the DCC random dragon generator to create the base creature then converted it to 5e.

My group went in with a do-or-die attitude, as they figured, if they can’t beat Hexia they have no chance against Typhon (Sydon), who is the next target on their list.  The sorcerer also created a DC 29 glass-steal dome to keep Hexia from flying as well. But it also meant no escape for either side.  One PC died during the battle.

NB: I use an abbreviated stat block for my monsters.  Just makes them easier to read in combat and easier to convert to other games like OSR.  It should be easy to decipher. One call out, I use the AC number for all DCs as well.


Ancient Mercury Dragon (Purple/Orange in hue)

Gargantuan dragon, lawful evil

AC 21; HP 594/297; Speed 40 ft., fly 80 ft., swim 40 ft.

STR +8, DEX +8, CON +14, INT +4, WIS +10, CHA +11; +7

Skills Deception +11, Insight +10, Perception +17, Persuasion +11, Stealth +8

Damage Immunities Cold, Poison; Poisoned

Senses Blindsight 60 ft., Darkvision 120 ft., Passive Perception 27

Languages Common, Draconic

CR 22 (41,000 XP); Proficiency Bonus +7

  • Gonzo Spellcaster. Hexia knows the following spells which she casts at +8 and uses at will on the DCC spellcasting table:
    • 1st level: comprehend languages, magic missile (for those who dont have access to DCC roll a d20+8, if the roll is 1 to 12, the spell fails an nothing happens. Otherwise halve the number rolled and this is the number of magic missiles Hexia can cast. On a natural 1 she looses the ability to cast the spell until she takes a long rest)
    • 2nd level: phantasm
  • Amphibious. Hexia can breathe air and water.
  • Biomechanical. Hexia is a creature of flesh and metal.  She is cybernetic in nature.  She has disadvantage on saving throws vs lightning based attacks and takes an extra die of damage.  If she takes lightning damage she looses her fly speed until the end of her next round. However, she is immune to poison, poisoned state and any kind of disease.  She also can not be surprised.
  • Flexible Legendary Resistance (3/Day).If Hexia fails a saving throw, she can choose to succeed instead. She may also use legendary resistance to respond to a threat and cancelling an affect or action that is detrimental to her. For example, she can make a hit, miss.
  • Legendary Frightful Presence.Each creature of Hexia’s choice that is within 120 feet of her and aware of Hexia must succeed on a WIS saving throw or become frightened for 1 minute. On a natural 1 the target is stunned as well until the end of Hexia’s next turn. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature’s saving throw is successful or the effect ends for it, the creature is immune to the dragon’s Frightful Presence for the next 24 hours, however, they have -1d4 penalty on attack rolls for the rest of the encounter.
  • Spider Climb.The spider can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Actions (x3) @ +15 (Bite, Claw, Claw)

  • Bite. reach 15 ft. Hit: 3d6 + 10 piercing damage plus 3d6 fire damage.
  • Claw. reach 10 ft., Hit: 4d6 + 8 slashing damage.
  • Tail. reach 20 ft. Hit: 3d6 + 8 bludgeoning damage. Targets must make a STR/DEX saving throw or be knocked prone.
  • Cast a Spell. Hexia uses Gonzo Spellcaster.
  • Hypnotic Stare. Hexia can hypnotize targets with her gaze. She can gaze into the eyes of one target per round by using one action. A creature that meets her gaze must make a WIS save or stand stupefied as long as she holds its gaze.
  • Underbelly Crush. Targets an adjacent creature who must make a DEX saving throw or take 2d6 +10 bludgeoning damage and becomes grappled and restrained (Escape DC 21) as they are trapped under the dragons bulk. A creature trapped underneath Hexia’s bulk has line of sight and line of effect only to the brood mother, and no creatures have line of sight or line of effect to it. A creature that starts its turn grappled by Hexia takes 16 bludgeoning damage and 10 poison damage (from the dragon’s poison skin).
  • Green Flame! (Recharge 1d4+1). Hexia exhales green fire in a 90-foot cone (9 targets). Each creature in that area must make a DEX saving throw, or take 11d6 fire and 11d6 acid damage on a failed save, or half as much damage on a successful one.

Reactions (x1)

  • Bloodied Breath. When reduced to 50% of her original hit-points, Hexia’s breath weapon recharges and she uses it.

Legendary Actions (x3)

  • Cast a Spell. Hexia uses gonzo spellcaster.
  • Detect. Hexia makes a Wisdom (Perception) check.
  • Swirly Eyes. Hexia uses hypnotic stare.
  • Tail Attack.Hexia makes a tail attack.
  • Wing Attack.Hexia beats her wings. Each creature within 10 feet of her must succeed on a DEX saving throw or take 4d6 + 8 bludgeoning damage and be knocked prone. She can then fly up to half its flying speed.

Lair Actions (x1)

Lair actions trigger as the first thing that occurs in a round of combat.

  1. Grasping roots and vines erupt in a 20-foot radius centred on a point on the ground that the dragon can see within 120 feet of it. That area becomes difficult terrain, and each creature there must succeed on a DC 15 Strength saving throw or be restrained by the roots and vines. A creature can be freed if it or another creature takes an action to make a DC 15 Strength check and succeeds. The roots and vines wilt away when the dragon uses this lair action again or when the dragon dies.
  2. A wall of tangled brush bristling with thorns springs into existence on a solid surface within 120 feet of the dragon. The wall is up to 60 feet long, 10 feet high, and 5 feet thick, and it blocks line of sight. When the wall appears, each creature in its area must make a DC 15 Dexterity saving throw. A creature that fails the save takes 18 (4d8) piercing damage and is pushed 5 feet out of the wall’s space, appearing on whichever side of the wall it wants. A creature can move through the wall, albeit slowly and painfully. For every 1 foot a creature travels through the wall, it must spend 4 feet of movement. Furthermore, a creature in the wall’s space must make a DC 15 Dexterity saving throw once each round it’s in contact with the wall, taking 18 (4d8) piercing damage on a failed save, or half as much damage on a successful one. Each 10-foot section of wall has AC 5, 15 hit points, vulnerability to fire damage, resistance to bludgeoning and piercing damage, and immunity to psychic damage. The wall sinks back into the ground when the dragon uses this lair action again or when the dragon dies.
  3. Magical fog billows around one creature the dragon can see within 120 feet of it. The creature must succeed on a DC 15 Wisdom saving throw or be charmed by Hexia until initiative count 20 on the next round.

Encounter Terrain

  • The logs in this room are floating in water two to three feet deep. Accordingly, the squares with logs in them are challenging terrain, requiring a DEX (Acrobatics) check with disadvantage when the character tries to enter into melee with Hexia (who remains in the water but will fly if that is advantageous to do so). Characters who fail the check fall prone and end their turn.  They must make a successful check to enter melee with Hexia. The brood mother is big enough to ignore the logs.
  • The water is strongly poisonous; a creature that drinks the water takes 4d10 + 10 poison damage and ongoing 10 poison damage (save ends, probably when the incautious PC retches the water back up). A character who is knocked prone in a water square may swallow some inadvertently; avoiding this requires a CON ability check. The water area is difficult terrain. 

Regional Effects

The region containing a legendary green dragon’s lair is warped by the dragon’s magic, which creates one or more of the following effects:

  • Thickets form labyrinthine passages within 1 mile of the dragon’s lair. The thickets act as 10-foot-high, 10-foot-thick walls that block line of sight. Creatures can move through the thickets, with every 1 foot a creature moves costing it 4 feet of movement. A creature in the thickets must make a DC 15 Dexterity saving throw once each round it’s in contact with the thickets or take 3 (1d6) piercing damage from thorns.
    Each 10-foot-cube of thickets has AC 5, 30 hit points, resistance to bludgeoning and piercing damage, vulnerability to fire damage, and immunity to psychic and thunder damage.
  • Within 1 mile of its lair, the dragon leaves no physical evidence of its passage unless it wishes to. Tracking it there is impossible except by magical means. In addition, it ignores movement impediments and damage from plants in this area that are neither magical nor creatures, including the thickets described above. The plants remove themselves from the dragon’s path.
  • Rodents and birds within 1 mile of the dragon’s lair serve as the dragon’s eyes and ears. Deer and other large game are strangely absent, hinting at the presence of an unnaturally hungry predator.


If the dragon dies, the rodents and birds lose their supernatural link to it. The thickets remain, but within 1d10 days, they become mundane plants and normal difficult terrain, losing their thorns.


In addition to what is listed:

A broad oni flashes below the cold moon,
His silvery sheen should not shine so soon.
For when his blade cleaves foes asunder
They need not be buried six feet under.

A plain, undecorated magical kanebo (greatclub) that glows faintly in the moonlight. Scattered among the eggs are 200 jade figurines representing drakkin soldiers, each worth 25 gp (total of 5,000 gp). This replaces the silver coins in the hoard. When he slays a foe, there is a 50% chance the body is finely splattered across all nearby surfaces and a 50% chance they rise as a zombie or other undead (hostile to everyone, including the wielder).


Posted in 5e, Clash of the Titans, Dungeons & Dragons

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