Law of Ueki

The story starts out with the Battle of the Supernatural Powers, a tournament to decide who will be the next God of Heaven.

Each candidate (100 in total) is required to choose a junior high school student (middle school) 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 (才, Zai), 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 King of the Celestial World Candidates / God Candidates. The punishment for breaking them is that the King of the Celestial World Candidate / God Candidate is sent to Hell.

• King of the Celestial World Candidates / God 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.

• King of the Celestial World Candidates / God Candidates are only allowed to grant a power to one individual. However, it is possible for two King of the Celestial World Candidates / God Candidates to give a power each to one person; if found out, though, it will lead to a disqualification of both King of the Celestial World Candidates / God Candidates.

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 / God, the winning team votes which of the King of the Celestial World Candidates / God Candidates should be given that honor.

Level 2 powers may be obtained by the power users. The requirements are a total mastery of their original power and the powerful desire to become stronger.

All heavenly beings have the potential to master a total of ten attacks which correspond with different levels of their growth. These attacks are called Jingi, or "sacred treasures". Higher level sacred treasures have a higher damage capability than lower ones. If a heavenly being is a power-user (having received a power from a God Candidate), their power is merged with their sacred treasures. In the case of Ueki, he manifests these abilities through his talent of tree growth. A heavenly being's sacred treasures with no special powers will take the form of stone. In the Battle Game, there are only six heavenly beings: Ueki, Robert, Kilnorton, Diegostar, Balo and Ban Dicoot, but only Ueki and Robert use level 2 sacred treasures.

Every middle school student have talents that help them in battle or in life. An important rule in the tournament to prevent power users from attacking anyone they please is that the power user will lose a talent if they attack a non-power user, but they can gain a random talent by knocking out another power user. If the power user loses all their talents, they will vanish.

Ueki starts the series with eleven talents: Girl charisma, ability to study, ability to run, accuracy, sarcasm, ability to dance, lottery, animal charisma, ability to swim, ability to dodge, and the ability to imitate. However, those soon begin to dwindle down because of his desire to protect innocent civilians with his powers, a source of endless frustration to Mori.