The recent trailer for Pokémon Legends: Arcrues revealed the Diamond Clan and the Pearl Clan, who reside in the Hisui region. These clans have their own leaders, yet there is a disconnect between the names of these characters, even though they are meant to reference Pokémon Diamond and Pearl. The Hisui region from Pokémon Legends: Arceus is the ancient version of the Sinnoh region from Pokémon Diamond and Pearl, yet there are lots of connections between the games, despite the time difference between their events.
The initial trailers for Pokémon Legends: Arceus suggested that the Hisui region was devoid of human life, and the Galactic Expedition Team was part of a push to build settlements in the area. It turns out that there are groups of humans that live in the Hisui region, in the form of the Diamond Clan and the Pearl Clan. The leaders of the two clans don't get along and they are seen arguing in front of Commander Kamado in the recent trailer.
In Pokémon Legends: Arceus, the Diamond Clan is led by Adaman, and the Pearl Clan is led by Irida. Adaman's name is a specific reference to the Sinnoh region, yet Irida's is not. There's a reason why Pokémon Legends: Arceus is only half-referencing the events of Pokémon Diamond and Pearl, and it's related to items that were used to summon the Legendary Pokémon that appeared in the Sinnoh region.
Pondering The Pokémon Orbs
Adaman is named after the Adamant Orb, which is the item used to summon Dialga in Pokémon Diamond. This naming convention isn't used with Irida and it's easy to see why. In Pokémon Pearl, Palkia is summoned using an item called the Lustrous Orb. If Pokémon Legends: Arceus was going to shorten the name of this item for the leader of the Pearl Clan, then it would mean having a character with the word "lust" in their name, which wouldn't be a good fit in a game meant for kids.
The name Irida likely refers to the word iridescent, which refers to something that has luminous colors that shift, depending on the angle at which they are viewed. Iridescent is a word that is often used to describe pearls, so it's a fitting choice for the leader of the Pearl Clan. It remains to be seen whether either of the orbs (or the Griseous Orb from Pokémon Platinum) will appear in the game, but if Pokémon Diamond and Pearl are being referenced in such a specific way, then it's a safe bet that the orbs and their associated Legendary Pokémon will appear in Pokémon Legends: Arceus.
Pokémon Legends Arceus releases for the Nintendo Switch on January 28th, 2022.