In my opinion, Tierno, Trevor and Shauna all play a part, be it big or small, in your adventure in X and Y. For Tierno, he loves dancing and Pokémon that learns and dancing related moves (Swords Dance, Petal Dance). Remember his Corphish back at Route 5 and 7 that learns Swords Dance and he had Roserade that learns Petal Dance and two other Pokémon at Route 19. Trevor is a really nice boy and he seems rather knowledgeable about Pokémon and he always compares the Pokédex with the player and eventually battling you in Route 7 and Route 19 and he has a pretty neat team, consisting of Raichu, Aerodactyl and Florges. For Shauna, I felt that she was more like a little sister whom just likes to go on adventures with her friends and just take joy in every little thing she finds cute and I like how she will give you her starter Pokémon after you beat the game. Not to take note that they are all kids.
