Calastryx

In the Dawnforge Mountains high above the mortals of Hammerfast, the three-headed dragon Calastryx is eager to unleash her wrath upon the Nentir Vale and destroy everything in her path.
Biding her time deep within the mountains, an evil waits to be released. Calastryx, the three-headed red dragon, is a legend to the people of Hammerfast. The history of this beast is shrouded in mystery and mistruths, yet one fact remains—if Calastryx is ever released from the wizard’s curse that imprisons her, havoc would engulf the Nentir Vale.
Dragons of the Vale: Before the dwarves settled Hammerfast, a commune of dragons lived near that region in the Dawnforge Mountains. These dragons considered themselves rulers of the vale and constantly raided the groups of nomadic people that were attempting to settle the land. The people of the vale could not mount an effective defense. Eventually, help arrived from the dwarves of Hammerfast and the dragons’ attacks lessened, allowing civilization in the vale to grow. The dragons still pose a credible threat to the folk of the vale and the citizens of Hammerfast. Many people are concerned because the attacks have increased in frequency recently and no one is sure why.
The Founding of Hammerfast: After years of the dragons’ raiding, the people trying to settle in the vale sought out any who could help quell such assaults. Their answer came in the form of the dwarves. Their thane sent a battalion of heavily armored dwarf warriors to establish a forward operating fortress near the Dawnforge Mountains. The dwarves named it Hammerfast, and it was there that the people of the vale first met Calastryx.
Origin Unknown: Calastryx is a vile and perverse creature, born of the mutations of entropy and evil magic. Some speculate that she was the creation of some long-forgotten god, while others believe she has always existed in one form or another. No matter the truth, the fact remains that she exists to destroy anything in her path, and she should be feared and respected. She currently slumbers from a curse placed upon her by the wizard Starris nearly three hundred years ago, but that slumber is nearly over.
Three Heads, One Plan: Each of Calastryx’s three heads came to an agreement long ago about how they would work together during combat. Preferring to take out the most obvious threat, Calastryx will go out of her way to ensure that her enemies are effectively terminated. Most often, Calastryx will send the lesser forces serving her to the front to take the brunt of attacks while she uses her reach to slash, bite, and immolate foes. Fearing little because of her size and might, Calastryx will slay allies with her blazing breath if it is tactically advantageous to do so (such as when few or none of her allies are in the area it affects). Calastryx attempts to herd her enemies into a tight group so that each of her heads has an opportunity to unleash its breath. If an opponent survives such an onslaught, Calastryx will stay back from it, using her reach to shred the offender. If any enemy tries to flee or gain a tactical advantage over her, Calastryx moves that enemy into a more vulnerable location with a bite attack.
The Emberdark Kobolds: The kobolds of the Emberdark tribe were nearly hunted to extinction by the dwarves of Hammerfast, but they survived by hiding in the Dawnforge Mountains. Lately, their numbers have grown. The tribal elders have received signs from mighty Kurtulmak, exarch of Tiamat, that Calastryx is nearing freedom. The Emberdark kobolds are gathering a trove to win her favor and become her loyal servitors. So far, their efforts have yielded modest results, although Emberdark pillagers wearing armor with shoulder guards shaped like second and third kobold heads (in honor of Calastryx) have been sighted in the foothills. Whether Calastryx will accept such servants is unknown