Lugia is a dual-type Psychic/Flying Legendary Pokémon introduced in Generation II.
It is not known to evolve into or from any other Pokémon.
It is often considered to be part of the Tower duo with Ho-Oh, even sometimes as Ho-Oh's polar opposite. Silver represents Lugia as "guardian of the seas", and Gold represents Ho-Oh as "guardian of the skies." Lugia is also the trio master of the Legendary birds.
Lugia is the game mascot of Pokémon Silver, its remake Pokémon SoulSilver, and Pokémon XD: Gale of Darkness (as Shadow Lugia), appearing on the boxart of them all.
In Pokémon XD, Shadow Lugia, codenamed XD001, is a main part of the storyline, and Cipher's ultimate Shadow Pokémon.
Lugia leads the legendary birds. When they fight over territory, Lugia is the only Pokémon that can quell their ceaseless fighting, as observed in the second Pokémon movie. Much like the birds, it possesses the ability to control the weather; most notably, it can calm and give rise to storms. It is said that a light flutter of its wings is capable of causing winds powerful enough to tear down cliffs. If it were to flap its wings, it could hypothetically spawn storms lasting as long as 40 days. It is highly intelligent, and because of the devastating power it could accidentally inflict, it isolates itself deep underwater and tends to sleep in solitude. Lugia is the only known Pokémon that learns Aeroblast. It is extremely rare and is hardly ever seen.