The Mamodo King (魔界の王 Makai no Ō, "King of the Demon World") is the supreme monarch of the Mamodo World. To become King a mamodo must be chosen to take part of "The Battle to Decide the Mamodo King Tournament." Whoever wins the tournament will be declared the Mamodo King.
The King's Privilege
The King's Privilege grants the Mamodo King, right after the tournament, the power to make anyone he disagrees with or dislikes to be eliminated in order to make the Mamodo World the King's ideal world. The Mamodo King will also be granted all the knowledge of the Mamodo World to know each and every Mamodo, so as to have as much time knowing which Mamodo to be granted life using their judgment from that knowledge.
Main article: Wand
The Mamodo King is granted the power of a wand, which has the power to prevent any mamodo spells from activating within 50 meters of the wand while granting the holder the ability to still use them. This generally ensures the Mamodo King's protection from any attackers.
However, in the case that the wand is stolen and used by another mamodo to attack the current King, a spellbook may immediately go towards the mamodo's partner in the human world, where the partner can recite a spell and observe what was happening to the Mamodo King. When using a spell, because the spell uses the human's own power (and because the caster is out of the wand's range), the wand cannot nullify it. This was shown as when Zatch was being attacked by another mamodo that was using the wand, Kiyo obtained the spellbook to use Baou Zakeruga to defeat the mamodo. However, right after the threat was neutralized, the spellbook leaves the partner immediately.
The spellbook reappearing is likely an emergency function of the Mamodo Battle to ensure that the current Mamodo King's reign is not interfered with should the wand fail.
- Dauwan Bell - The father of Zatch and Zeno. He won the last tournament 1000 years ago and loves his sons and his Mamodo World very much. He sent Zatch to live like a normal child when Zatch was still a baby because he was the only one capable of wielding the power of Bao. He made Zeno undergo cruel military training because he inherited his father's bloodlust and ruthlessness, even if it meant he would become resentful towards him and Zatch. During Zatch's enthronement to become the official King of the Mamodo World, he was seen with his wife and his son Zeno in the Ceremonial Hall, smiling.
- Zatch Bell - The current King of the Mamodo World, who granted all the souls of the mamodo world bodies again after he won the Tournament .