Hello everyone. I have some interesting information for you all about the situation of Legendary Pokémon in Pokémon Sword and Shield. I managed to pay a handsome amount of money to some inside sources for this info.

First off, none of the Legendary and Mythical Pokémon will be transferable from the older games except for Meltan and Melmetal. This means that the available Legendary Pokémon must be obtained in Sword and Shield in order to use them.

The first set of returning Legends are Articuno, Zapdos, Moltres, Raikou, Entei, Suicune, Latias, Latios, Cresselia, Mesprit, Thundurus, Tornadus, and Landorus. All of these Legends were roaming Legendaries at some point in previous games, which is fitting considering that you obtain them in the Wild Area.

Each set of Legends can only be unlocked during post-game by speaking to certain NPCs returning from older games and encountered in Max Raid Battles. Of course, some of them are version exclusives.

Zapdos (Sword) and Moltres (Shield) are unlocked by talking to Blaine and having both of them in your team when you speak to him again allows you to unlock Articuno.

Suicune (Sword) and Raikou (Shield) are unlocked by talking to and battling Ethan, Silver, and Lyra. It's a Double Battle where you choose to team up with either Hop or Marnie and Ethan teams up with Silver or Lyra respectively. Speaking to Ethan again with the two Legends unlocks Entei.

Latias (Shield) and Latios (Sword) are unlocked by speaking to Wally who's specifically from Ruby, Sapphire, and Emerald. If either Legend is battled in Max Raid Battles, they will always hold a Soul Dew.

Mesprit (Sword) and Cresselia (Shield) are unlocked by speaking to Roark and Byron.