Riolu is a small, blue, canine Pokémon. It has a black torso and legs, a blue tail, and a yellow collar. It has rounded bumps on the backs of its forepaws. It has a black "mask" and red eyes. It stands on its toes instead of its entire foot. It is sensitive to a special type of energy called Aura; however, it does not have the ability to fully use these powers, although it can still emanate these waves to communicate and sense them, albeit only in ripples. It has developed two black appendages that hang down from its head, which rise when Riolu reads or manipulates aura. It has even been seen that Riolu can sense and react to Aura before they even hatch. The aura emitting from Riolu's body grows even stronger when it is frightened or sad.

Like most Fighting-type Pokémon, Riolu naturally has superhuman strength, stamina, and endurance. It is capable of making long journeys on foot in a short amount of time. It is a playful, energetic, and loyal Pokémon. Riolu will read the minds of humans to assure whether or not they are pure of heart.

Lucario possesses a great deal of strength and is selfless in its approach, much like its Trainer. While it has a stoic manner, its good intentions are clear. Lucario works completely in sync with Riley, making them a formidable duo of Aura Guardians. It relies on its aura abilities which provide Riley with incredible insight, as seen through their Team Galactic counter-operation.

When Ash and his friends traveled there after being contacted by Barry, they found the local Steel-type Pokémon fighting brutally against each other. When a crazed Aggron attacked Ash, Riley stepped in and had Lucario attack it with Close Combat. Despite being a Steel-type as well, Lucario wasn't affected like the others of its type due to its strong aura. With Lucario’s aura, they found the source of the problem: A machine operated under Mars's command that was using the Spear Key to create low frequency waves which tortured the Steel Pokémon.

Even then, however, Lucario wasn't completely under the machine's influence and tried to destroy the machine but couldn't do it. Lucario attempted to read the Aura coming out of the machine, but at that time, Mars placed the Spear Key into a pillar at the Iron Ruins. The pulses of energy beam overwhelmed Lucario and caused it to rebel against Riley, even breaking its Poké Ball in half when he tried to recall it.

Ash managed to finish the job and destroy the machine, so Lucario and the other Steel types were brought back to their senses. When Mars realized her plan was shot, she fled and attempted to blow up Iron Island with explosives, but her efforts were thwarted when both Riley and Lucario used their auras to contain the blast and send it flying. Following the arrival of Professor Carolina, Riley and Lucario decided to remain on Iron Island to investigate the Iron Ruins further.