A dragon sovereign has a mystic bond with youthful true dragon, a bond that guarantees the dragons loyalty to the sovereign (as long as it is treated with respect), and allows the dragon sovereign to tap into some of the dragon’s arcane power. A character that begins on the dragon sovereign mythic path is approached by a dragon of his choice as a prospective bonded mount within 30 days of obtaining a sovereign relic. Once approached, the character is then considered a 1st tier dragon sovereign and gains a dragon mount. He is assumed to have already bonded with the dragon. The bond causes the dragon to grow slightly in size, and drives it to gain power as its dragon sovereign gains experience, rather than as it gains age categories. Many of a dragon’s normal powers (spell-like abilities, spellcasting, unlimited breath weapon use) are either suspended or modified as the arcane power that drives them is used to fuel the bond between dragon sovereign and dragon mount. This bond, once forged, ends only if both sovereign and dragon decide to end it, or if one is killed and not resurrected in a timely fashion.
Most true dragons are unwilling to undergo this bond (though there is always one that will do so and is able to find a dragon sovereign without a dragon mount). For good dragons this is often done to aid good-aligned dragon sovereigns in facing the evils of the world. In some cases it is part of ancient pacts dating back centuries or even millennia that dictate service of a set number of dragons of a given bloodline. Even among neutral and evil dragons however, there are always a few who seek out such bonds willingly.
The reason for this is a desire for power, and an ability to take a long view. A dragon mount bonded to a dragon sovereign grows in size and power as the dragon sovereign gains experience. The payoff comes when the dragon sovereign dies, though dragon sovereigns often live as long as their mounts, due to their mythic nature. At first, if the dragon sovereign dies, the dragon mount simply must survive as an underpowered dragon, but after a year and a day from its sovereign’s death if it has no not bonded with a new dragon sovereign, the dragon begins to gain the full power of a normal dragon of its size (or the oldest category in its size class, to a maximum age category of very old).
Consider a red dragon wyrmling. It is Small, and won’t reach Large size for roughly 20 years. It won’t be Huge for 45 years, and Gargantuan size is at least 4 centuries off. But if that red serves as a dragon mount, it becomes Large immediately, and stands a fair chance to become Gargantuan within a few years. If it survives its dragon sovereign’s loss, the red dragon will gain the full power of a very old dragon within a few years, jumping its (ubiquitous) plans for world domination ahead 6 centuries. While most red dragons feel the price is too high, there are always a few youngsters willing to serve now (though somewhat grudgingly, see the Focus score in the descriptions of dragon mount, below) for hundreds of years worth of powers later.
A dragon mount can carry its dragon sovereign immediately, as it is Large size. Dragons’ carrying capacity is modified for their size as normal creatures, and as bonded dragon mounts they can fly (at full speed) even if heavily encumbered. A dragon can carry two creatures one size smaller than it, four creatures two sizes smaller, and sixteen creatures three or more sizes smaller (all assuming it has the Strength to do so).
A dragon mount can carry its dragon sovereign as soon as it is the same size category as its dragon sovereign, assuming it’s strength is great enough to bear the dragon sovereign and his gear. A dragon mount’s carrying capacity is modified for its size as normal creatures, and as bonded dragon mounts they can fly (at full speed) even if heavily encumbered. A dragon mount can carry two creatures one size smaller than it, four creatures two sizes smaller, and sixteen creatures three or more sizes smaller (all assuming it has the Strength to do so).
The link between dragon sovereign and dragon mount grows in strength as the dragon sovereign gains levels, allowing them to communicate more easily, feel each other’s location, and even transfer life essence to one another. The abilities the dragon mount gains with his dragon sovereign are listed on Table: Dragon Mount Base Statistics.
A dragon sovereign’s dragon mount functions in all ways as a dragon steed from the Dragonrider* class except for the following changes.
Breath Weapon (Su): The dragon mount breath weapon deals an amount of base damage multiplied by 1/2 the dragon sovereign’s class level (minimum x1) and its range increase as shown on Table: Dragon Mount Base Statistics. This otherwise functions the dragon steed’s breath weapon* ability.