Tenkaichi Budoukai

The Tenkaichi Budoukai(, Lit. "Strongest Under Heaven Martial Arts Tournament") is an ancient and ceremonious and momentus event that occurs time and time again throughout history. It was originally the term given to the event in history where martial artists gathered. They would fight mercilessly to the death, till only one stood supreme above all. He whom accomplished this was  to assume absolute control over the world of martial arts and becoming the ruler of the earth, the emperor of all fighters. He whom accomplished this was given the name of the one and only Ikkitosen(, Lit. "Matchless Warrior").

Description
During the times of primordial earth, before the age of humanity, the gods would converge and pit their strengths against one another. This caused mass devastation and destruction throughout earth, forcing humans to stay away and hide themselves during this event which later became called The Tenkaichi Budoukai. Since that time, many mortals have replicated this ceremony, transforming it into the world martial arts tournament. What the implications of this event mean, is essentially the one whom wins is granted absolute wealth and power for all eternity, that is, until the next Tenkaichi Budoukai begins.

History
As mentioned above, the gods would converge on earth and fight to see whom was the strongest. This act would later be replicated by descendants of those gods whom desired that their blood, clansmen, and corresponding ancestor were the rightful owner of the title of Ikkitosen. The "first" Tenkaichi Budoukai happened many years before the start of the mainstream Dragon Ball manga, transpiring at the end of The Freedom Age, a battle that was so huge that it effectively ended the era alltogether, and destroyed the entire worlds government, social standing, military, police force, economy, and more, forcing the human race to adapt and rebuild under new circumstances. After this point, the true purpose of The Tenkaichi Budoukai was destroyed so as to keep the winning family in power for all eternity. The Tenkaichi Budoukai later became a mere civilian attraction for the masses to mindlessly flock to for entertainment, while any and all relations to the 12 Noble Housholds were cut off and destroyed, having those clans becoming subservients of the winner.