Riolu and Lucario are two of the most popular Pokémon and they’re both in Sword and Shield for trainers to find and battle alongside.
The aura wielders, however, are incredibly difficult to find. They only appear in the Wild Area (Giant’s Cap) in a certain section of it and only during snowstorms.
If there isn’t a snowstorm in the area, these Pokémon won’t spawn at all, so be sure to either wait until the weather changes in the subsection or come back another day or time to have a shot at seeing them.
Riolu also has a five-percent chance of appearing and Lucario spawns occasionally as one of the ultra-powered Pokémon around the area.
You can, of course, evolve a Riolu into a Lucario if you manage to capture one. To evolve it, you need to max out Riolu’s happiness and level it up during the day to turn it into a Lucario.
Other than Giant’s Cap, the only other way to get these two Pokémon is through Max Raid Battles. These are incredibly hard to find, however, and might even be more rare than just catching the Pokémon in the wild.