The story starts out with the Battle of the Supernatural Powers, a tournament to decide who will be the next god of The Celestial World (rendered as God Candidates in the Animax version and Kami (天界人) in the Japanese version).
Each candidate (100 in total) is required to choose a junior high school student to act as their fighter. The student is given a unique power and told to eliminate as many enemies as possible. The winning God Candidate will become The New God of Heaven and the winning student will receive the Blank Zai (or talent), a talent that can be anything they choose.
While this leads many students to thoughts of greed and selfishness, Kosuke Ueki decides to take it upon himself to win this tournament to keep that power away from those that would abuse such a gift.
Initially, fights in the tournament consist of a battle between two power users - one wins by knocking the other opponent out.
When a knock-out is obtained, the loser will lose their power and the winner will gain a talent Zai (才), which is a talent of some sort (e.g. "talent of running," "talent of studying," and so on). A power user who has lost a fight is disqualified and their power is labeled "retired."
The rules for the combatants of the tournament revolve around the talents:
Power users are not allowed to use their powers against non-power users, or they lose one talent for each hit.
If the power user loses all of his/her talents, then he/she will disappear.
Every time a power user knocks out another power user, he/she will gain another talent, senseless or not.
If, for any reason, both contestants become unconscious at the same time, the round is a draw: no talents will be gained, and no powers are lost. The contestants must be knocked out within 5 seconds of each other, or the last contestant wins.
There are also rules which apply to the Celestial World Candidates, also known as God Candidates. The punishment for breaking them is that the candidate is sent to Hell.
Candidates are not allowed to interfere with their power user's fight. This means that they are not allowed to provide their power users with more supplies to use their power (this may only apply to during a fight), or even save them from dying.
Candidates are only allowed to grant a power to one individual. However, it is possible for two candidates to give a power each to one person; if found out, though, it will lead to a disqualification of both candidates.
Candidates cannot harm any non-power users, the same rule apply on power users.
Near the end of the tournament, power users are allowed to form groups of five for "battle royale"-style fighting. Knock-outs during this stage do not result in losing powers. Each team is given a penalty if it loses, such as having all of the members die or losing their hair in addition to losing their powers.
To decide who receives the Blank Talent among the winning team, a device is used to measure the growth in power that each participant has shown from the beginning to the end of the tournament. To decide who is to become King of the Celestial World, the winning team votes which of the candidates should be given that honor.