If you meant an actual official Pokémon game or a different fan game (like Pokémon Xenoverse, which has a Quetzal-like legendary), let me know and I can clarify.
Quetzal offers freedom rarely seen in official titles. From the moment you start, you can tailor your experience: wiki pokemon quetzal
: Includes Pokémon from multiple generations beyond the original Hoenn region. If you meant an actual official Pokémon game
It sounds like you're looking for information on , a popular multiplayer ROM hack. which has a Quetzal-like legendary)
If you want this adapted into a full Pokédex page, fancard, sprite sheet notes, or a short in-universe lore article, tell me which format.