The Overlord was the creator of the Etherial Army and the original source of all evil in the world of Vestroia. A sinister incorporeal entity, the Overlord first appeared as a manifestation of negative energy itself that challenged the First Dragonoid to battle for the fate of Vestroia. The battle went on for a while, with the Overlord creating the Etherial Army in order to win. Yet The First Dragonoid emerged victorious, defeating the Etherial Army and trapping the Overlord in the Doom Dimension.
Years later, when Cyrus was abandoned in the dimension by Name1 and the other Group1 generals, he was confronted by the Overlord spiritually, who influenced him to stand by his side and embark on a quest to destroy Vestroia and Gundalia/Neathia. The Overlord gave Cyrus command of the Etherial Army, and guided him as he strengthened their forces and oversaw the construction of an ultimate weapon. Yet eventually, the Overlord revealed he was using Cyrus all along, and he took control of his body - commencing a metamorphosis that turned him into a giant Mechtogan Destroyer, and set off to Earth, which the Overlord desired to re-create as a base for his army. The New Dawn and BattleTech returned to Earth where they fought the Etherial Army until Diego faced off against the Overlord. In the midst of the battle, Diego unlocked the True Potential for his Unstable Bodily Transformation, and managed to destroy the Overlord's Mechtogan Destroyer form in the process, freeing Cyrus and returning him to his original body.
All was at peace for a while, until the Overlord returned in the form of a spirit once more. With the help of Name2 and the Group2, the Overlord set out to complete an ancient prophecy known as the threat of Sarcophagus - an almighty being with the powers of the original warrior, from whom the first Dharaknoid and Dragonoid were descended from. Using the Sacred Orb, the prophecy was fulfilled and the Overlord gained his almighty physical form once more, and fulfilling the prophecy, evolved. As he put the world in a greater danger than it ever had before, The New Dawn, BattleTech, and Group3 arrived to thwart his plans, yet he proved too strong an adversary. In a final effort to defeat him, Diego sacrificed himself to defeat the Overlord, destroying his physical forms in the process. However, it seemed the Overlord had some strength left in him, but he was destroyed in a single blast from Drake. As the balance must be maintained, the Overlord survived the ordeal, yet his spirit is dormant. A statue of The Overlord is expected to be placed in the Hall of Bakugan.
The Overlord was credited with the creation of the Etherial Army, implying that he may possess powers similar to Code Eve. In his orb (Spirit) form, he was able to float freely, allowing him to accompany Cyrus wherever he traveled in the Doom Dimension. He also appeared to have some form of enhanced perception, as he can immediately sense any arrival in the Doom Dimension. After using Cyrus's body to retake a physical form, the Overlord gained enhanced physical strength, high durability, and the ability to release energy from his appendages. He usually fired this energy as offensive beam attacks, but he could also use it to shield himself; by releasing small "jets" of energy from his lower pair of hands and legs, the Overlord was able to hover in the air or propel himself at varying speeds. In his true form, the Overlord's strength and durability increased even further, due to his impenetrable armor. He could fly or levitate at will, breath energy, and spit masses of pure evil that corrupt anything they hit (much like Doom's Evil Energy shots). At the end of his battle with Diego, he displayed the ability to transform himself into a large orb of shadows that engulfs his foe - within the orb, he could grew to many times its original size, although it is unclear if the rest of his body was still present or if the Overlord could simply manifest parts of himself at will within the sphere. When he became the legendary "Sarcophagus" he could shoot beams of invisible Energy. Also he was able to use invisible Energy to levitate any object in mid air. He could even manipulate the objects. The Overlord was able to shape dust particles into a massive arm and hand in a attempt to crush the opposition. He could also catch others with beams of Purple Energy which he had shaped like a colossal spider web. Despite all these traits he was defeated by Diego.