>>33509636There's no rule that says there can't be more than one of any given legendary species.
Hell, in the
anime there are known to be multiple Articuno and Zapdos, as well as multiple Lugia.
In the games, there are several cases of NPCs using legendary Pokemon as well. "Legendary" almost always determines them to be rare rather than there only being one.
Obviously there are Pokemon of which only one exists. Pokemon like Mewtwo, Lugia, Ho-oh, Kyogre, Groudon, Rayquaza, Dialga, Palkia, Giratina, and other "mythical" Pokemon.
