Rick is a very cocky and somewhat unfriendly young man, typically calling the player and Rodney a loser, and his primary motivation throughout the game is to become the greatest Trainer in the whole region.
After the events on Rassic City, the player finds out that Rick is the brother of Rassic Castle castellan Lizzy, a known expert in Dragon-type Pokémon and Mega-Evolution. His parents told you that Rick is hotheated because he always stand in the shadow of his famous sister.
Quotes
At Serpentine City
At Thundrome Pass
At Rustbolt City
At Brushus Town
At Battle Bridge
At Docking Port
Sprites
Rick's Trainer sprite from Solar Light & Lunar Dark