Dragon, Mithral, Ancient

Family: Dragon - Mithral

Gargantuan dragon, neutral

Armor Class 20 (natural armor)
Hit Points 490 (28d20 + 196)
Speed 40 ft., fly 80 ft.

12 (+1) 26 (+8) 25 (+7) 20 (+5) 21 (+5) 20 (+5)

Saving Throws Dex +15, Con +14, Wis +12, Cha +12
Skills History +12, Insight +12, Perception +19, Persuasion +12, Stealth +15
Damage Resistances force
Damage Immunities slashing
Condition Immunities charmed
Senses blindsight 60 ft., darkvision 120 ft., passive Perception 29
Languages all, telepathy 120 ft.
Challenge 22 (41,000 XP)
Proficiency Bonus +7


  • Legendary Resistance (3/Day). If the dragon fails a saving throw, it can choose to succeed instead.
  • Magic Resistance. The dragon has advantage on saving throws against spells and other magical effects.
  • Mithral Scales. If the dragon succeeds on a saving throw by 5 or more against a spell that targets only it, the dragon is unaffected, and the spell is reflected back at the caster as though it originated from the dragon, turning the caster into the target.


  • Multiattack. The dragon uses its Frightful Presence. It then makes one Bite attack and two Claw attacks.
  • Bite. Melee Weapon Attack: +15 to hit, reach 15 ft., one target. Hit: 19 (2d10 + 8) piercing damage. Instead of dealing damage, the dragon can end one magical effect of its choice of 7th level or lower on the target.
  • Claw. Melee Weapon Attack: +15 to hit, reach 10 ft., one target. Hit: 15 (2d6 +8) slashing damage, and if the target isn’t a Construct or Undead, it must succeed on a DC 23 Constitution saving throw or lose 10 (3d6) hp at the start of each of its turns as a piece of metallic claw breaks off in the wound. Any creature can take an action to remove the claw with a successful DC 16 Wisdom (Medicine) check. The claw pops out of the wound if the target receives magical healing.
  • Tail. Melee Weapon Attack: +15 to hit, reach 20 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage.
  • Frightful Presence. Each creature of the dragon’s choice that is within 120 feet of the dragon and aware of it must succeed on a DC 20 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end 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.
  • Shard Breath (Recharge 5–6). The mithral dragon spits metallic shards in a 90-foot cone. Each creature in that area must succeed on a DC 22 Dexterity saving throw, taking 73 (21d6) slashing damage on a failed save, or half as much damage on a successful one. The area becomes difficult terrain for 1 minute, then the shards dissolve into wisps of silvery smoke. When a creature moves into or within the area, it takes 7 (2d6) slashing damage for every 5 feet it travels.


The dragon can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The dragon regains spent legendary actions at the start of its turn.

  • Detect. The dragon makes a Wisdom (Perception) check.
  • Tail Attack. The dragon makes a Tail attack.
  • Wing Attack (Costs 2 Actions). The dragon beats its wings. Each creature within 10 feet of the dragon must succeed on a DC 23 Dexterity saving throw or take 15 (2d6 + 8) bludgeoning damage and be forced prone. The dragon can then fly up to half its flying speed.


Mithral dragons are attracted to lairs near humanoid civilization, where petitioners can reach them if their diplomatic services are needed. Unlike other dragons, mithral dragons forsake lairing upon remote natural caverns or cliffs, preferring to dwell in impressive structures of metal and stone—with a particular fondness for towers. More than once, a mithral dragon has accepted the deed to a fortress, palace, or castle as payment for brokering peace between warring factions.

Curiously, mithral dragons don’t hoard coins and precious metals as most dragons do. Other curiosities fill their lair, like fine paintings, marble statues, rare tomes, stained glass, and anything made of mithral—rare treasures procured over a lifetime of interacting with mortal creatures.

On initiative count 20 (losing initiative ties), the dragon takes a lair action to cause one of the following effects; the dragon can’t use the same effect two rounds in a row:

  • Impaling Spikes. Metallic spikes sprout from the ground beneath one creature the dragon can see within 120 feet of it. The target must make a DC 15 Dexterity saving throw. On a failure, the creature takes 10 (3d6) piercing damage and is restrained as it is impaled on the magical spikes. On a success, a creature takes half the damage and isn’t restrained. A creature, including the restrained target, can take its action to free the restrained target by succeeding on a DC 15 Strength check to break the spikes.
  • Shimmering Scales. Light within the lair bends toward the dragon, reflecting brilliantly off its scales. Each creature within 30 feet of the dragon and that can see it must succeed on a DC 15 Dexterity saving throw or be blinded until the end of its next turn.
  • Wave of Peace. A pulse of calming energy washes over the lair. Each hostile creature the dragon can see within 120 feet of it must succeed on a DC 15 Charisma saving throw or become indifferent about creatures of the dragon’s choice that it is hostile toward for 1 minute. This indifference ends if the target is attacked or harmed by a spell or if it witnesses any of its friends being harmed. When the effect ends, the creature can choose to become hostile again.


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

  • Calming Air. Humanoids within 6 miles of the lair experience feelings of peace and are less prone to mood swings. Dragons within 6 miles of the lair experience the opposite effect, becoming plagued by anxiety and irritability.
  • Peaceful Realm. When a Dragon or Humanoid within 3 miles of the lair attempts to commit an act of violence against a Dragon or Humanoid and that act of violence isn’t in self-defense, that creature must succeed on a DC 13 Wisdom saving throw or be unable to commit acts of violence, other than self-defense, for 1 minute. The dragon can choose to suppress this effect for any creature.
  • Shining Mithral. Objects made from metals other than mithril appear dull and feel heavy while within 1 mile of the dragon’s lair. If the dragon dies, these effects fade over the course of 1d10 days.


Light glints off the dragon’s glossy scales, shining silver-white. Its tiny wings folded flush against its body open like a fan and expose shimmering, diaphanous membranes. Its narrow head, with bare slits for its eyes and nostrils, sits at the end of a slender neck atop an impossibly thin frame.

Rage in Youth. Younger mithral dragons raid and pillage as heavily as any chromatic dragon, driven largely by greed to acquire a worthy hoard, though they are less likely to kill for sport or out of cruelty. In adulthood and old age, however, mithral dragons are less concerned with material wealth and more inclined to value friendship, knowledge, and a peaceful life pursuing interesting goals.

Peacemakers. Adult and older mithral dragons are diplomats and arbitrators by temperament (some dragons cynically call them referees). They enjoy bringing some peace to warring factions. Among all dragons, their strict neutrality and ability to negate magic make them well suited to these vital roles.

Section 15: Copyright Notice

Tome of Beasts 1 ©2023 Open Design LLC; Authors: Daniel Kahn, Jeff Lee, and Mike Welham.

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