Tierno is a tall, heavy-set boy with black hair in a short back and sides that also resembles the leaves on Chespin's head. One of his most noticeable feature is that he has a rather overweight physique. Even so, this hardly seems to impact his desire to be a dancer. He is shown wearing a large black T-shirt that has a Vanillite design on it, orange cargo shorts, a yellow backpack, and matching black and yellow sneakers. Tierno also wears a yellow watch with a black wristband.
Tierno is a friendly person, who supports his friends, including Trevor and Shauna, in pursuing their goals. Tierno is also a talented dancer and uses such a tactic in his battles to prevail.
Tierno and his friends, Trevor and Shauna, met at Professor Sycamore's lab, where Tierno chose a Squirtle for his starter Pokémon. Tierno bid his friends farewell, though they tended to meet each other in certain places. While on the journey, Tierno also practiced his dancing moves, along with his Squirtle.
Season 17: XY
Tierno came to the Pokémon Summer Camp, along with her friends, Shauna and Trevor, forming Team Squirtle. Tierno, who finished the battle against a trainer with a Conkeldurr, noticed Serena and took Shauna to show Serena, the one who made notable Pokévision videos. Tierno was pleased to watch such videos, considering Shauna was making some as well. Later on, the heroes were allowed to have a battle with the opponent of their choosing, so Ash chose Tierno to battle, using his Froakie to battle Squirtle. Tierno wanted to make a dancing squad - a Pokémon team that could use his rhythm strategy.
With a few days being passed, Tierno, in the fishing competition, managed to fish out a Magikarp. Later, Sycamore dismissed the teams, who would have to make a Pokévision video. At the end of the day, Team Squirtle showed their video, where Tierno expressed his desire of becoming a dancer, along with his Squirtle. While Team Squirtle did not receive any points at the end of the day - making Tierno sad by that fact - they were reminded they were tied with Team Froakie for having an equal amount of points.
The following day, Tierno, with the rest of his team, had to collect some stamps in a race. In the first part, Tierno sent Squirtle to climb a part of the mountain and receive his first stamp. Tierno, however, made a mistake and nearly fell down, but Ash's Froakie released his frubbles to cushion Tierno's fall. After collecting the stamp, Tierno followed his friends, Shauna and Trevor, to other parts of the race, but stopped and decided to help find Bonnie, who somehow got lost. Going through the forest, both teams found Bonnie, unconscious, on the other end of the cliff. Ash managed to jump onto Drifloon and Drifblim to get to Bonnie and carry her on his back. When returning, Ash tried to jump to the other side, but he was too far and started to fall. Clemont extended his Aipom Arm and reached Ash, Pikachu and Bonnie up, who were lifted back by Serena, Tierno, Trevor, and Shauna. Bonnie woke up and confessed she saw a strange Pokémon in the woods, which everyone noticed. Despite neither team having won the race, Tierno did feel it was a good experience to have seen the mysterious "X" Pokémon.
On the last day of the Pokémon Summer Camp, the teams were to pair up and participate in a battle tournament. This pleased Tierno, Shauna, and Trevor, since they have been known to battle together and make combination attacks. Before the tournament began, Team Squirtle came to the cooks - who were the Team Rocket Trio - and were told they needed to hand over their Pokémon for health inspection at the Pokémon Center. Tierno gave his Squirtle, Shauna her Bulbasaur and Trevor his Charmander. After some time, Team Squirtle visited the Pokémon Center and were shocked to hear the cooks did not give her the Pokémon. The heroes joined Team Squirtle in finding the missing Pokémon. They found the cooks and Pikachu removed the tablecloth, revealing Team Squirtle's Pokémon had been captured and bound by Leech Seed. Team Rocket removed their disguises and attacked with Inkay and Pumpkaboo. Clemont's Bunnelby used Dig, distracting Team Rocket and allowing Froakie to free the Pokémon by using Cut on the vines. Later on, Team Squirtle faced Team Froakie in a three-on-three battle. Tierno had Squirtle use its dancing moves to confuse its opponents. Fennekin tried to use Hidden Power but was defeated by Squirtle's Aqua Tail. Clemont and Ash worked together and defeated Tierno, Shauna, and Trevor. Despite the loss, Tierno knew they all gave their best. During the night, before everyone went off, Ash asked Tierno for advice, wanting to learn about dancing moves, since he would face Korrina in Shalour City soon. Tierno taught him some moves, reminding through it, one can even predict the opponent's moves. The following day, Tierno went off, bidding farewell to his friends.
During Ash's Gym match against Korrina, Ash had thought of Tierno and Squirtle and stopped using the dancing strategy, since it is Tierno's battling style, not Ash's.
Season 18: XY Kalos Quest
Tierno met Ash, Serena, and Bonnie, who were going to Lumiose City. Tierno admitted he obtained the Voltage Badge, but from a robot in Lumiose City's Gym. Tierno showed he also obtained new Pokémon after leaving the Pokémon Summer Camp and even had his Squirtle evolve into a Wartortle. Tierno and Ash were to have a quick battle, with Tierno using Raichu and Wartortle against Ash's Pikachu and Sliggoo, but an odd machine came to them. The machine, made by Team Rocket, took Pikachu, so Sliggoo used Dragon Breath to free him. The machine was damaged and took Raichu and Wartortle instead. Tierno teamed up with Bonnie and Sliggoo and went to search for his Pokémon. Jessie, enraged Wartortle used Water Gun on her, had Pumpkaboo use Shadow Ball, causing the machine, containing Raichu and Wartortle, to be knocked off the cliff, near Bonnie and Tierno. After Bonnie had Dedenne send out a pulse to warn Pikachu the machine is coming after it, the group came to a boulder, where Sliggoo, Raichu, and Wartortle combined their attacks to shatter the rock. They arrived in time for Sliggoo to use Dragon Breath to free Pikachu, who was captured by the machine. Jessie had Pumpkaboo use Shadow Ball, which hit the machine by accident and caused it to explode, as well as creating a fire around everyone. Tierno witnessed as Sliggoo used Rain Dance to douse the fire and evolved into a Goodra. After Goodra defeated Team Rocket with Dragon Pulse, Ash and Tierno had their battle. While Tierno had Raichu and Wartortle attack Goodra, Goodra stored energy and unleashed Bide, which hit Raichu and Wartortle. Wartortle attempted to attack but was knocked onto Raichu and defeated. Later, Tierno bid Ash, Serena and Bonnie farewell, who soon reached Lumiose City.
Tierno came to support Shauna in her next Showcase and noticed the heroes arrived as well. Tierno showed his Wartortle evolved into a Blastoise and admitted he also fought in Anistar City's Gym but lost. Tierno wanted to give more details, but Ash wanted to check it out himself first. Serena, who was worried about Eevee's shyness, had an idea and had a Tag Battle with Shauna's Ivysaur against Ash's Pikachu and Tierno's Blastoise. Tierno's Blastoise attempted to attack with Rapid Spin and Water Gun, but the attacks were negated. Blastoise used its rhythm strategy, but Tierno was also impressed and surprised Eevee also wanted to utilize such a strategy, even surpassing Blastoise. The battle stopped, as Serena had an idea for Eevee's performances. Nevertheless, Tierno continued the battle with Ash, having his Blastoise use Hydro Pump to counter Thunderbolt. The following day, everyone rushed out of the Pokémon Center, as Serena and Shauna forgot to register for the Showcase.
The following day, Tierno watched the performances with Ash, Bonnie, and Clemont. Upon learning Serena's Eevee was missing, everyone was searching for it, only for Eevee to run back to Serena. After the matter was settled, everyone came back to watch the performances and Tierno gave his vote. During the end of the day, Shauna and Tierno bid farewell to the heroes and ran off, since they had to help Trevor find his missing stuff, for Trevor lost them while taking pictures of other Pokémon.
Season 19: XYZ
Tierno and Trevor came to the Kalos League Tournament. Before the opening, they encountered Ash and his friends. Tierno admitted they watched the Master Class Tournament and while he was saddened Serena did not win the title of the Kalos Queen, he claimed for him, she will always be his queen, which made Serena blush. Tierno promised to give his best during the battles. He also gazed at the screen and found his opponent for tomorrow's battle. Seeing Trevor would battle Alain, Tierno claimed Trevor should use his ace, which made Ash quite curious what they were talking about. During the Kalos League Tournament, Tierno watched Trevor battling Alain and saw Trevor using his Key Stone to Mega Evolve his Charizard. Tierno pointed out Trevor worked hard for the Kalos League. Tierno was also surprised Ash was nearly disqualified, as he came late for his battle against Titus, a battle Tierno also watched.
Tierno battled Sawyer for the place in the semifinals, during the Kalos League Tournament. Tierno sent Ludicolo and danced with it, while Sawyer sent Aegislash. Tierno managed to battle Sawyer, having Ludicolo use Rain Dance, followed by Hydro Pump. Tierno and Ludicolo taunted Sawyer and Aegislash, thinking they may not counter their attacks. Sawyer overcame that by having Aegislash use King's Shield to protect itself, as well as Sacred Sword, which defeated Ludicolo. Next, Tierno sent Raichu, who fired Charge Beam but was countered by King's Shield. Instead, Raichu used Dig and defeated Aegislash, so Sawyer sent Slurpuff. Slurpuff immediately used Attract, which infatuated Raichu. Tierno was frustrated, as Raichu ignored his commands and got hit by Slurpuff's Energy Ball. Tierno swapped Raichu with Blastoise, who easily defeated Slurpuff with Hydro Cannon. For his last Pokémon, Sawyer sent Sceptile, who evaded Blastoise's Hydro Cannon and hit it hard with Leaf Blade. Daunted by Sceptile's speed but confident that Blastoise outmatched it in power, Tierno had the Water-type use Skull Bash, but it was sent flying by Sceptile's Frenzy Plant. Before Blastoise fell down defeated, it used Rain Dance. Tierno sent Raichu back and had her use Thunder, which, due to the rain, made it an unmissable attack. However, Sawyer Mega Evolved his Sceptile, who took no damage from the attack, as its new ability, Lightning Rod, negated all electrical damage. Dodging Focus Blast, Mega Sceptile defeated Raichu with Dragon Claw. Tierno, who was defeated, called Raichu back and decided to support the winner.
Tierno watched Ash battle Sawyer. He also noted while Sawyer's strategy was similar to Ash's, but there were some differences, thinking it was their auras. He also thought Slaking was bluffing when it took so many attacks and wondered how Ash will face Aegislash's King's Shield move. Tierno realized Sawyer's Aegislash's strategy was to limit Pikachu's movement. Once the battle ended, Tierno was glad Ash won the battle. The day before the finals, Tierno ate some sweets with Trevor and Shauna. As Mairin passed by, Trevor saw Chespin and realized it was Clemont's. Soon, the group found the heroes and Mairin gave Clemont's Chespin back. The heroes thanked Tierno, Shauna, and Trevor, who pointed out Mairin found Chespin. The group came to the Pokémon Center, where Mairin told them about her own Chespin. They were also approached by Professor Sycamore, who informed them about Ash's Greninja's transformation power. The next day, Tierno sat by his friends to watch the finals between Alain and Ash.
Tierno was watching the Kalos League finals and was glad to see Ash won the first battle, knowing it would give him the advantage later on. Tierno admitted the battle made him anxious since both Ash and Alain were very powerful and were giving their all. Tierno continued watching the battle; he and Tierno how Alain had only Bisharp and Charizard, making him at a disadvantage. Once Alain won the battle, Tierno and Shauna were slightly sad that Ash lost, seeing he was really close to snatching the victory. In the end, even with Ash losing the battle, Tierno was still glad Ash had put a great match that amazed everyone. Since the chaos broke out on the streets of Lumiose City, Sawyer teamed up with Tierno, Shauna, and Trevor to help the citizens. The group managed to protect the citizens and send them to a safe place, where they tended to the citizens. Tierno, Shauna, Trevor, and Sawyer came to Diantha, wishing to help out amidst the chaos. Thus, Diantha had them rescue elders and children, then escort them to safety. Tierno, Shauna, Trevor, and Sawyer watched Team Rocket's broadcast about Team Flare and the megalith. They were happy the megalith was stopped and destroyed in the end.
Eventually, Tierno met up with his friends and was glad the heroes survived the battle against the Megalith. He was happy to watch the Showcase made by Shauna, Serena, and Jessilee, which also made him dance. The next day, after Grace bid farewell to them and left by bus, he wanted to train dancing with Serena but was reprimanded by Shauna. Either way, Tierno left to investigate the case of Pokémon running away from Lumiose City. Shauna, Tierno, and Trevor were doing professor's task by examining the area with wild Pokémon.
- 7 unknown badges
- Voltage Badge
Lumiose Conference: Quarter-Finals (Lost to Sawyer)
- ^ a b XY038: Summer of Discovery!
- ^ XY039: Day Three Blockbusters!
- ^ XY040: Foggy Pokémon Orienteering!
- ^ XY041: Battling Into the Hall of Fame!
- ^ XY043: Showdown at the Shalour Gym!
- ^ XY065: Good Friends, Great Training!
- ^ XY080: Performing with Fiery Charm!
- ^ XY090: Tag Team Battle Inspiration!
- ^ XY091: A Performance Pop Quiz!
- ^ XY112: Master Class is in Session!
- ^ XY113: Performing a Pathway to the Future!
- ^ XY125: A League of His Own!
- ^ XY126: Valuable Experience for All!
- ^ XY127: Analysis Versus Passion!
- ^ XY128: A Riveting Rivalry!
- ^ XY129: Kalos League Passion with a Certain Flare!
- ^ XY130: Finals Not for the Faint-Hearted!
- ^ XY131: Down to the Fiery Finish!
- ^ XY132: A Towering Takeover!
- ^ XY133: Coming Apart at the Dreams!
- ^ XY135: Rocking Kalos Defenses!
- ^ XY136: Forming a More Perfect Union!
- ^ XY138: The First Day of the Rest of Your Life!
- ^ XY140: Till We Compete Again!