After the completion of the story line, Tierno can be found in Coumarine City, asking to see a Pokémon knowing a randomly selected dance move each day, giving the player a Heart Scale if his request is fulfilled.
Tierno also appears as one of the player's partners in the Battle Maison when choosing Multi Battle.
"All right! Nice to meetcha! You know, it'd feel like we were a closer crew if we called each other by nicknames. Can I call you <player's name's first letter>-Meister/Lady <player's name's first letter>?"
"I know right? It was such a cool feeling when Trevs and I met our Pokémon! Hope you feel the same way we did!"
"Oh lighten up, Trevs! You're way too serious sometimes. Um, <player's nickname>... Please take this with you, too. It's a letter from the professor. He said you should give it to your mom."
"All right! We're done with our errand for the professor. I guess Trevs and I will go look for Pokémon! Let's go, Trevs!"
"Oh! Hey there, <player's nickname>! Are you here to get your Pokémon healed, too? Pokémon Centers sure are great. You can talk to the lady at the counter and have her heal your Pokémon. And you can even deposit Pokémon you've caught in that PC! Know how Pokémon are sent to a PC when you've caught more than you can carry? That's where they go! Oh yeah, <player's nickname>! There's a Poké Mart in the back of a Pokémon Center. IT's a good idea to stock up on Poké Balls and Potions and stuff at the Poké Mart, too."
"Yeah! They're just like a dance team made up of Pokémon, aren't they?"
"Nope! Even during Pokémon battles, I'm always checkin' out their moves! And then my feet just starting moving, too! I can't even help it, y'know? Like with Swords Dance! I love it! I guess that's why I can never win…"
"Oh, hey, it's <player's nickname>! Do your Pokémon know any sweet moves? Show me in a battle!"
"That was some nice footwork!"
After being defeated
"Well, yeah, Trevs! Coming up with the world's best Pokémon dance IS my dream, after all! I was born to dance! I won't ever stop! Not with moves like this!"
If talked to after the battle
"Man, I really want to meet a Pokémon that can use the move Teeter Dance. Then I'd wanna dance with it, right?"
"Hey, <player's nickname>! How's your journey going?"
"Get this! I've found some great Pokémon dancers!"
"That's right! He did say that! Ummm... Who were we supposed to say hello to again?"
"Oh, that's right! He did say that! Well, I guess we should look for the Mega Evolution guru, then! Where do you think he is anyway?"
On beach section
"<player's nickname>, check this out! Isn't this stone cool? I got it from this person called the wandering stone collector for showing off my dance moves! It might be a Mega Stone! Here, <player's nickname>, you can have it!"
Are you sure?:"I want you to have it, 'cause you're such a great Trainer and all... I still remember our battle on Route 5."
"That's the Tower of Mastery? Sooo cool! Well, I'll go call Trevs, then. Go on ahead, OK?"
"Yep! As you can see, we're doing great! Thanks for asking! We worked together to save the Pokémon connected to the stones on Route 10! I mostly left battling with Team Flare to Sina and Dexio, though..."
"<player's nickname>! Can we have a Pokémon battle? Oh, uh...sorry to just throw that at you..."
"It's weird, but… I don't get that down when I lose to you."
After being defeated
"Geosenge Town made me think… If <player's nickname> hadn't been there, I wouldn't be dancing now, that's for sure. That made me want to get to know <player's nickname> better, and I thought a battle would be the best way to do that. It's kinda selfish of me, I guess. But it's also a way of thanking him/her!"
"He's/She's off training with the Mega Evolution guru. He/She said friends are friends even if they can't be together."