Latias is female and has higher defensive stats, while Latios is male and has higher offensive stats. Their signature moves are Mist Ball and Luster Purge, respectively. They are the first legendary Pokémon to have specified genders.
In the games, Latias and Latios can hold the Soul Dew to raise their Special Attack and Special Defense stats by 50%. Rather than banning the duo, this item has been banned from official tournaments since Generation III.
Latias and Latios made their anime debut as the starts of Pokémon Heroes, wherein they were shown to be siblings who lived in Alto Mare. The duo were guardians of the Soul Dew, which was itself contained the soul of a deceased Latios.
A card of both Latias and Latios was released when Pokémon Heroes premiered in Japanese theaters. The card also featured stars of the previous movies: Mewtwo, Lugia, Entei, and Celebi.