The Kingdom Stone is the crystalline concentration of the energy supply from the starship that brought the Ancient Dragons of the Before Time to Avalice. It is used by the Avalicians to power their technology. According to the Royal Magister, the Three Kingdoms of Avalice have all depended on the Kingdom Stone's power for centuries.
Before its destruction, the Kingdom Stone resembled a sparkling crystal orb and had the colors of opal (purple) and sapphire (light blue). After its destruction, it becomes a crystalline vortex of the same colors and has most likely became the planetary ring that surrounds Avalice, as shown after the time skip.
By the time Lord Brevon and his army crashlanded on Avalice, the strength of the Kingdom Stone's power was weakening, unable to keep up with the growing energy demands. Desperate to avert an energy crisis in Shang Mu, Mayor Zao hires Spade to help his Soldiers steal it from the Ancient Temple in order to not only preserve his city's power, but also to increase his chances for a re-election. Around that time, Brevon had invaded Shuigang, murdered the King and brainwashed his son Dail, the only Heir to the Throne, to steal the Stone to recharge his Dreadnought so he could continue his galactic conquest, leaving the planet on the approach of civil war. However, Brevon's plan to turn the Three Kingdoms against each other backfires after a surviving Chaser named Torque, and a group of young girls called Team Lilac, manages to unite the armies of Shang Tu and Shang Mu with the aid of the Holodragon. Both armies then launched an assault on the Dreadnought's refueling station in the snowfields. But by the time they reach the Dreadnought, it makes liftoff with only Torque and Team Lilac managing to get onboard, where they come face-to-face with Lord Brevon and the full force of his Army.
After defeating an Upgraded Syntax and a Mutated Serpentine, Lilac & Carol make their way to the Dreadnought's warp drive. Just as they were about to reclaim the Kingdom Stone with one of Torque's hacking devices, Brevon stop their attempt by capturing Milla and turning her into a Mutant Monster, forcing her to attack her friends. Milla is defeated and falls into a death-like coma after turning back to normal. Lilac & Carol become enraged, and they break through the last of Brevon's defenses and make their way to the power core of the Dreadnought, where they confront and defeat Brevon. After the battle, the Dreadnought explodes, taking the Kingdom Stone with it. All hope seemed to be lost, until the Stone's energy transformed into a crystalline vortex that hovers over the Avalice, spreading unlimited energy across the planet, marking a new beginning for the Avalicians.
Over the course of 2 years, the Kingdom Stone's new form has improved life on Avalice. However, the destruction of it's physical form has resulted in the awakening of Merga, a ruthless Water Dragon who was sealed in a crystal prison during Avalice's oldest and deadliest war, and hidden deep in the ocean off the coast of the island chain, Parusa. The Kingdom Stone's power was used to keep Merga imprisoned within the crystal prison, but it's power grew weaker following the Stone's destruction, allowing Merga to break free. Now she seeks vengeance upon the Avalicians and sets out to "Purify the World" by exposing dark secrets about the Leaders of Avalice and resurrecting the ancient superweapon, Bakunawa.
- The Kingdom Stone's role bears a few similarities to the Master Emerald in the Sonic franchise.
- Both artifacts originally resided within deep underground caves on the planets they reside in.
- Both villains of their respective franchises were successful at kidnapping their respective artifacts from their resting place(s) (Lord Brevon in Freedom Planet, and Dr. Robotnik in Sonic 3).
- There are a few differences however, between these two relics:
- The Kingdom Stone is spherical and Crystal-blue colored, whilst Master Emerald is Diamond-shaped and Emerald-green colored.
- The Kingdom Stone's energies power machines and perhaps the entire world of Avalice, whilst the Master Emerald sustains the energies of an entire island and controls the energies of a few objects.
- The Master Emerald's energies are of Chaos origin. It is currently unknown what energies The Kingdom Stone is made up of, most likely elemental energies or perhaps another unknown or unnamed energy source once wielded by the Dragons of the past (if the latter is true, then it is also unknown if this energy still exists on Avalice in the present day).