Zorua and Zoroark definitely felt legendaryish, much for the same reasons as Riolu and Lucario. Zorua seems pretty rare in comparison to Riolu though, which can be found in pretty much every game since its debut.
zorua may as well be a mythical pokemon in the unova region considering how stupidly impossible it is to get one now in the games it debuted in
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I also thought all the Ultra Beasts were considered legendary Pokemon, too, when they were first announced, but it turns out they aren't legendary. I even went as far as to say, "oh, so Ash caught a legendary, huh?" When he caught Poipole in the anime... It wasn't until that Legendary Pokemon quiz on the Pokemon website. Can you blame me, though? The Alola games treated them like they were special, so anyone would make the mistake that they are legendaries, right?