Formerly a planet named Vulcan, Sol is now a star that rules over the Solar System. He was once good friends with the first reincarnation of Mercury. Dedicated to the well-being of his domain and subjects, Sol is strong, yet unlike Cosmos, he isn't immortal. He is already aging and ill when the 2nd Giganum Tournament commences, which is partly held to find his successor.
This saga begins with the appearance of the Great Nebula Swirl, a massive cloud of cosmic energy that emerged near the edge of the Universe. Cosmos, Ruler of the Universe, curious about the Swirl's sudden appearance, discovers planets emerging from it. Vulcan, a planet full of vigor and a fiery personality, was among the first to emerge.
Cosmos decided to host a massive battle royale among these ten planets, known as the 1st Giganum Tournament, for fame, glory, and a special prize, with dire consequences for the defeated. Vulcan befriended Mercury, sharing a positive attitude and fire manipulation abilities. However, their friendship was tested in the tournament's final stage. Reluctantly, they fought, and Mercury sacrificed himself, allowing Vulcan to win.
The defeated planets, except Vulcan, were banished into the Void, a dark, empty region, and presumed lost forever. Angered by the outcome, Vulcan demanded Cosmos return the others, but Cosmos instead transformed Vulcan into a star, erasing his planetary memories, and renaming him Sol.
Sol governed the Solar System with kindness and strength, wielding the mighty hammer Tempest and ruling more justly than Cosmos. He felt an unexplained closeness to Mercury, unknowingly his former friend. As Sol's life force rapidly depleted, posing a black hole threat, Cosmos organized the 2nd Giganum Tournament to find a new ruler, marking another pivotal chapter in this cosmic story.
