Yellow dragons are the physically weakest of the chromatic dragons.  However, they are by far the fastest in terms of flying and swimming speeds. While other dragons may rely on physical might, the yellow dragon knows that its speed is the key to defeating its foes. Despite their physical weakness the yellow dragon is a frustrating opponent for another dragon, as it can easily avoid the claw, fangs and even breath weapons of its rivals.

A yellow dragon has a lithe, serpentine body covered in white-flecked yellow scales.  Their scales change little throughout their lives, remaining an iridescent yellow color with a bluish shine in the light along the scales of their underbellies, although their colors do lose some of their vibrancy with age.  Its head is narrow and snake-like, with emerald eyes.  Their long forked tongue that flickers out from between its fanged jaws. A frill of quill-like spikes runs along its back from between its horns to the tip of its tail. Usually, these spike lie flat against the dragon's body.  When the dragon is agitated, or attempting to make itself look more impressive, they stand erect.  Among all dragonkind, they have the one of most distinctive and easily recognized odors; the scent of salt.

They are such self-centered creatures that they speak their own tongue, and can barely be bothered to learn standard draconic, or any other language for that matter, unless it directly suits their interests.  This makes dealing with them especially difficult, even for other dragons.  However, yellow dragons are utterly despised by the rest of dragonkind, especially bronze dragons, so it's unlikely another dragon will want anything to do with a yellow dragon beyond killing it on sight.

One reason yellow dragons are so despised is due to them working against their own kind during the Thousand Year War, working for the giants and betraying their own kind in exchange for treasure.  Another reason is that yellow dragons will steal and devour the eggs of bronze dragons; a vile taboo among all dragons.

Scholars speculate that should a yellow dragon breed with a blue dragon, their progeny would be a green dragon.  While most might dismiss such a theory, it isn't as outrageous as it first appears.  A yellow dragon's preferred environment could very easily bring it face to face with a blue dragon, and interestingly enough, a yellow dragon is immune to lightning damage.  Salt is technically poison, in large enough concentrations, and green dragons have a poisonous breath weapon. Green dragons also prefer forests, a climate seemingly halfway between the blue dragon's preferred arid deserts and the aquatic seaside preferred by the yellow dragon.  However, this theory has little solid evidence, and has yet to be proven.

Sea and Sky. Yellow dragons are just as at-home in the water as they are in the air.  They will live anywhere with open sky or open waters, preferably with high concentrations of salt, which the dragon consumes to supplement its diet.  Water is by far their favorite element; specifically along coasts or near salt lakes, but they can also be found living in desert salt flats.  If possible, a dragon will construct its lair underwater.  Otherwise, they prefer to build burrows in sand, which they prevent from collapsing in on itself by encrusting the walls in salt.

Ambush Predator. The yellow dragon is a vicious predator and will attack virtually anything, even attacking much larger creatures.  They are confident that their speed will ultimately allow them to win out, even if merely through a battle of attrition as the dragon nimbly dodges its foes attacks.  Their ability to fly, swim, and burrow makes them a dangerous foe, able to attack from above or below, regardless of terrain.  The dragon’s favorite tactic is to swoop past enemies, too fast for them to strike, using its breath weapon to blind and restrain them in a pillar of salt.  It then attacks the helpless victim with claws and fangs. Though seemingly confident in their superior speed, they are actually rather cowardly.  If faced with a superior opponent the yellow dragon's speed can't compensate for, it will not hesitate to flee, taking to the sky, surf, or burrowing through the earth.

Lord of the Deep. Yellow dragons along the seacoast sometimes cooperate with sahuagin. Sometimes sahuagin serve as guards and servants of a salt dragon, offering it tribute in the form of food and treasure.  In return the dragon provides protection from rival tribes, ixitxachitl, aquatic elves, tritons, or other such threats.  A yellow dragon of sufficient power, however, may simply conquer the sahuagin, enslaving them to build an empire under the waves.  A yellow dragon makes for a capricious and cruel ruler, and its servants live in fear of the consequences of displeasing it.

A yellow dragon's lair is usually a submerged cavern or tunnel at the bottom of a deep body of water; preferably seawater.  If deep enough water can't be found for its lair, a yellow dragon will burrow beneath the sands of a beach or desert, shoring up the walls with a thick crust of salt.  Regardless of where it is established, a yellow dragon's lair will contain flooded and non-flooded passage ways.  In the case of a desert lair, the dragon will dig until it strikes groundwater.

Lair Actions

On initiative count 20 (losing initiative ties), the dragon takes a lair action to cause one of the following effects:

• The dragon causes solid minerals to become a pool of flowing brine in a a 40-foot cube centered on a point it can see within 120 feet of it.  Nonmagical stone of any sort in the area becomes an equal volume of thick, flowing brine that remains until the dragon uses this lair action again.  The ground in that area becomes fluid enough that creatures can sink into it. Each foot that a creature moves through the brine costs 4 feet of movement, and any creature on the ground when the dragon uses this lair action must make a DC 15 Strength saving throw.  A creature must also make the saving throw when it moves into the area for the first time on a turn or ends its turn there. On a failed save, a creature sinks into the brine and is restrained, though it can use an action to end the restrained condition on itself by pulling itself free of the brine.  If the dragon uses this lair action on a ceiling, the brine falls. Any creature under the brine when it falls must make a DC 15 Dexterity saving throw. A creature takes 18 (4d8) bludgeoning damage on a failed save, or half as much damage on a successful one.
  
  When the dragon uses this lair action again, the briny pools formed from its previous use of this lair action reverts to solid minerals. Any creature in the brine when it transforms must make a DC 15 Dexterity saving throw. On a successful save, a creature is shunted safely to the surface in an unoccupied space. On a failed save, a creature becomes restrained by the crystallized minerals. A restrained creature, or another creature within reach, can use an action to try to break the crystals by succeeding on a DC 20 Strength check or by dealing damage to it. The crystalline mass has AC 15 and 25 hit points, and it is immune to poison and psychic damage.
• Pools of brine or water that the dragon can see within 120 feet of it surge outward in a grasping tide. Any creature on the ground within 20 feet of such a pool must succeed on a DC 15 Strength saving throw or be pulled up to 20 feet into the water and knocked prone.
• A cloud of salt swirls about in a 20-foot-radius sphere centered on a point the dragon can see within 120 feet of it. The cloud spreads around corners. Each creature in it must succeed on a DC 15 Constitution saving throw or be blinded for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Regional Effects

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

• The soil with 6 mile of the lair becomes salted and is rendered barren.  Plants wither, and life becomes unsustainable.
• Water sources within 1 mile of the lair are supernaturally fouled with drastically increased salt content, killing off most forms of life.  Fresh water becomes brackish water.  Brackish water becomes sea water.  Sea water becomes brine.  Brine becomes solid salt crystal formations. This effect also applies to water stored in a container that is brought into the area.

If the dragon dies, these effects fade over 1d12 months.  Rain or water currents may speed the process while drought or stagnation may slow it.