Trio master

A Pokémon that is a trio master is one who, in some way, oversees a legendary trio of Pokémon.

The trio master and the trio itself may relate in different ways. For example, Lugia is the trio master of the legendary birds; it is the only one who can quell their fighting when Lawrence III captures one of them in The Power of One.

In the games, the trio master sometimes will require that the members of its legendary trio be captured beforehand. In Crystal, Ho-Oh cannot be captured until all three of the legendary beasts have been captured, in Diamond, Pearl, and Platinum, Regigigas will not awaken unless the player has the legendary golems in his or her party, and in HeartGold and SoulSilver, Rayquaza is only obtainable after both Kyogre and Groudon have been obtained. Lugia and Arceus, however, do not seem to have this requirement, nor do Ho-Oh in Gold and Silver or Rayquaza in the Generation III games. In Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team, the legendary birds must all be befriended before the player can enter Lugia's dungeon, and before encountering Ho-Oh, the three legendary beasts must contribute their power to create the Rainbow Wing. In order to get Ho-Oh in Pokémon Colosseum, the player must first capture and purify all the Shadow Pokémon, which includes the legendary beasts, as one of the two requirements. In Pokémon Ranger: Locus of Light, the player needs to capture all 300 Pokémon in the regional Browser which includes the three legendary birds, to battle Lugia.

Trivia

• Rayquaza is the only trio master that is also a part of a trio. In the case of Rayquaza, it is the master of its own trio.
• The weather trio may be a reference to the three Jewish creatures, the Behemoth, Ziz, and Leviathan. As these Pokémon fit the description of them and have a similar role.

Trio master	Legendary trio
	Relationship
Lugia	Articuno	Zapdos	Moltres
	Lugia is the only one who can end the legendary birds' fight, as seen in the second movie.
Ho-Oh	Raikou	Entei	Suicune
	After the three Pokémon perished in the fire at the Brass Tower, Ho-Oh revived them.
Rayquaza	Kyogre	Groudon	Rayquaza
	Due to it ending the other two members' fight in Emerald, Rayquaza may internally be the master of the weather trio.
Regigigas	Regirock	Regice	Registeel
	Regigigas will awaken when the three legendary golems are brought to its residence. It is also said that it built statues made of rocks, ice, and magma.
Cresselia	Uxie	Mesprit	Azelf
Arceus	Dialga	Palkia	Giratina
	According to legend, Arceus created all three members of the dragon trio.