While somewhat similar to his video game counterpart, this version of Gladion is far more benevolent and less morally ambiguous.
In the Japanese version, he is voiced by Nobuhiko Okamoto, who also voices Katsuki Bakugo. In the English dub, he is voiced by Eddy Lee.
Gladion, as a young boy, watched as his sister, Lillie, was attacked by an Ultra Beast. Lillie was terrified, while Gladion was not brave enough to defend her. Suddenly, a Silvally arrived, which defeated the Ultra Beast. While Lillie lost memory of the encounter and became scared of Pokémon, Gladion took the Silvally as his own Pokémon, and swore to protect his sister.
One day, Gladion found an injured Eevee and brought it to Hobbes. Gladion was very concerned about Eevee, though Hobbes promised it would recover if they took it to the Pokémon Center. Gladion was also motivated to go on a journey to find out more about himself, as well as to train alone. Thus, he left Lillie and the mansion. Lillie kept a picture of her family in her room as Gladion was living elsewhere.
Pokémon the Series: Sun and Moon
Gladion was walking with Umbreon through the streets when he was ambushed by three Team Skull grunts. Gladion ignored them and continued walking, but the grunts demanded him to hand over his Umbreon. Gladion eyed them, as the grunts sent their Pokémon to attack. Instead, Gladion sent Lycanroc, who used Stone Edge to defeat all three of Team Skull's Pokémon. Gladion continued on and was seen by Team Rocket. He later challenged a sailor, and had his Lycanroc defeat the sailor's Blastoise, impressing the crowd. Ash observed the battle and was told by Rotom that Gladion was the famous trainer of the island. Ash went to Gladion and introduced himself, wanting to challenge him. Gladion ignored him but was called by Lillie, who addressed Gladion as her brother. Gladion was surprised, and when Lillie showed she could touch her Pokémon, Snowy, Gladion simply told how that was great and she should keep it up and refused to visit the mansion. He also saw Ash had a Z-Ring and was told by Ash that he got it from Tapu Koko. Seeing how Ash was important, Gladion decided to at least think of the challenge, then left. During the morning, Gladion sent Umbreon to deliver a letter to Ash to accept the challenge. Ash soon came, as Gladion told he wanted to battle him because of his ties with Tapu Koko. As the two had their Rockruff and Lycanroc battle, Team Rocket came and snatched Lycanroc and Pikachu. Ash's Rockruff managed to Bite the net and free Pikachu and Lycanroc. Gladion decided to finish this, as he used the Z-Ring to have his Lycanroc use Continental Crush, blasting Team Rocket away. Since Ash wanted to use the Rock-type Z-Move, Gladion advised him to challenge the Kahuna of Akala Island. Just as they were about to continue the battle, Lillie came and cheered for her brother. Since Ash had to go to school, Gladion told they should postpone the battle. He shook hands with Ash and left.
As Ash faced Olivia, who had her Lycanroc use Continental Crush, Ash remembered Gladion and his Lycanroc, the former having the latter use the same Z-Move. Gladion's Lycanroc heard Rockruff's howling on Akala Island. Gladion had Lycanroc to go investigate and be back by nighttime. Gladion went to a cave and sent his Type: Null out inside it. However, due to the strain of its helmet, it acted restlessly. Gladion ran over to Type: Null to comfort it and told it that everything would be fine. He exclaimed it would be a problem if someone saw it outside.
Pokémon the Series: Sun and Moon-Ultra Adventures
Later, Type: Null acted restless again as it sensed the birth of a young Cosmog named Nebby, forcing Gladion to keep it from going outside. Though it tries to resist him, Gladion reminded Silvally it would be a problem if someone saw it outside the cave. Gladion managed to calm it down, but it sensed the coming of the Ultra Beast.
Later, Gladion, Silvally, Lycanroc, and Umbreon were about to battle against a group of Pinsir, but Nebby teleported Ash, Pikachu, and Ash's Lycanroc to his location. They fell on top of the Pinsir and they attack them out of anger. Gladion's Silvally was able to chase them away, then started to walk too close to Nebby, which frightened the latter to the point of tears. Gladion calmed Silvally down, and asked Ash why did he have the Ultra Beast, Nebby. Ash denied Nebby was a dangerous one. Gladion became flustered, until Ash tells him that Solgaleo and Lunala trusted him to take care of Nebby. He admitted that Nebby Teleported him, Pikachu, and Lycanroc to his location because Ash wanted to show Gladion his Dusk Form Lycanroc, who is neither Midday or Midnight Form. Gladion told that they were at Ten Carat Hill. Ash told Gladion about Lillie's progress, that she managed to touch Pikachu, taking care of Snowy, and nicknaming Nebby. Gladion was shocked, and told Ash that Lillie was attacked by an Ultra Beast a few years ago, and was saved by Silvally. Due to that incident, Gladion believed Ultra Beasts were not worthy to live in this world, and swore to hunt Nebby down if it showed traits of the Ultra Beasts. He also wondered kind of trainer Ash was, since Tapu Koko personally gave him a Z-Ring, owns a strange Lycanroc, and Solgaleo and Lunala entrusted him with Nebby. Ash did not answer his questions, but believed he could learn more through a battle. Gladion used his Silvally for the first time in an official battle, while Ash used his Lycanroc. Silvally proved to be a powerful opponent, landing some powerful attacks, and dodging most of Lycanroc's despite its heavy mask. Silvally's Crush Claw eventually knocked Lycanroc into a nearby puddle, messing up its fur. With its fur ruined, Lycanroc flied into a fit of rage and attacks Silvally without Ash's commands, forcing Ash to restrain Lycanroc. Lycanroc's rage frightens Nebby, causing it to release a powerful screech which cleans Lycanroc's fur, calming it down. Ash and Gladion decide to continue the battle, and Silvally eventually defeats Lycanroc with Crush Claw. After the battle, Ash decided to head back to Professor Kukui's house, while Gladion knew this experience has strengthened Silvally and Lycanroc, too. Gladion ordered Ash not to say a word about Silvally to anyone, especially Lillie, before walking away.
A few days later, Nebby teleported Lillie to Gladion's location after she strongly desired to see him again. Gladion was startled, asking Lillie why she's there. Lillie was about to express her desire to spent time with him like before, but Silvally leapt right right in front of her. The sight of Silvally caused Lillie to partly remember the incident that caused her fear a few years ago. Gladion rushed over to a terrified Lillie, but Nebby teleported Lillie back to her classmates before he could reach her.
Later, Gladion came to Ash, furious for letting Nebby take Lillie to him. Gladion thought that it would've been better for Lillie if she never remembered the incident. He later returned to his hotel room, where Faba was waiting for him, and ordered "the young master" to return his Silvally. Gladion refused, remembering that Faba mistreated Silvally. and used Lycanroc and Umbreon to protect it. Faba used his Alakazam and Hypno to battle Gladion's Pokémon. Faba's Alakazam and Hypno's quickly overpowered Lycanroc and Umbreon with Hypnosis and Psychic. Gladion attempted to use his Silvally as a last resort, but Faba's Hypno used Hypnosis to render him unconscious. Gladion struggled to resist the powerful Hypnosis, but his vision became blurry and eventually fell unconscious, as Faba stole Silvally. The next day, Gladion went to Aether Paradise where he saw his mother, Lusamine, in her office. Gladion angrily demanded to know where Silvally was, but Lusamine was completely unaware of the situation. Though she remembered that it was a Pokémon that Faba created to fight Ultra Beasts, Faba had told her that the project failed. Gladion assumed that Faba had been lying, because Silvally had saved Lillie from an Ultra Beast a few years ago. While the two were searching for Silvally in Faba's office, Gladion informed Lusamine of the incident that happened a few years ago. Gladion furiously pointed out the Lusamine should've known this despite Faba's lies, and chastised her for her obsession with Ultra Beasts caused Lillie to become unable to touch Pokémon. Lusamine apologized to him, but Gladion stated that he was not the one that she should apologize to. Gladion finds Silvally's Premiere Ball, but heard an alarm coming from the basement. Gladion and Lusamine rushed down there, where they found Lillie being held in the air by Faba's Alakazam's Psychic, and Ash, Pikachu, Snowy, and Nebby being held down by Faba's Hypno's Psychic. Gladion sent out Silvally to save Lillie, who broke free from its mask to save Lillie from Alakazam's Psychic. The evolved Silvally saved Lillie, causing her to fully remember the incident that happened a few years ago. Gladion equipped Silvally with a Dark-Memory Disc, changing it into a Dark-Type Pokémon, and defeated Faba's Alakazam and Hypno with Multi-Attack, freeing Ash, Pikachu, Snowy, and Nebby from Hypno's Psychic. Having learned that the whole ordeal was a misunderstanding, Lillie apologized to Silvally and thanked it for saving her twice, and gave Silvally a hug, much to everyone's surprise and eventually begin touching Snowy, Pikachu, and even Nebby. Putting an end to her fear once and for all.
Sometime after Faba had escaped, Gladion was searching for him nonstop. He eventually visited his mother in her office, who asked if they found Faba. Lusamine denied, and as Gladion was about to continue his search, Lusamine stops him from leaving. She wanted to thank Gladion and to report they were still searching for Faba, but Gladion ignored her and left. After Faba kidnapped Nebby and disappeared, Gladion arrived to the Pokémon School. Told about Faba's newest incident, Gladion believed he was at Aether Foundation. To catch up to them, Lillie called upon a jet from her mansion. Gladion told Lillie to stay behind, but Lillie wanted to save Nebby too and insisted that she came along. Gladion was surprised by his little sisters determination, and let her come along with Ash, too. Along the way, they informed Lusamine of the situation. Along the to the basement, Gladion assumed that Faba plan was to use Nebby to summon another Ultra Beast. When they arrived in the basement, they saw Faba using a machine, trapping Nebby and using its power to create an Ultra Wormhole. While Ash tackled Faba, Umbreon destroyed the machines that was trapping Nebby with Shadow Ball. After Nebby was freed, it transformed, much to everyone's surprise. However, the machine absorbed enough energy to create an Ultra Wormhole and an Ultra Beast appeared - the same Ultra Beast that attacked Lillie a few years ago, which Faba named as UB01: Symbiont. UB01 then attacked everyone, so Gladion sends out Silvally to protect Lillie. UB01 proved to be too strong despite everyone's attempt to get it out of their world, and descended down to try to attack Lillie. Gladion was determined to protect his little sister, by letting UB01 take him away, but Lusamine pushed him out of the way and gets carried away through the Ultra Wormhole, leaving Lillie and Gladion horrified.
After Lusamine's abduction, Gladion approached Lillie, who was overwhelmed by the shock. While Wicke and Burnet were arguing with Faba, Ash wanted to help Gladion, who replied from then on, the issue became a family matter and did not accept his help. Regardless, Burnet advised them to return to Melemele Island, and the group went back home. At night, Gladion walked into Lillie's room, who lied to him about going to bed. Gladion knew Lillie was plotting something, looking at her new clothes and new hairstyle. Though Lillie still lied to him by saying it's her sleepwear, Gladion asked her how will she open a Ultra Wormhole. Lillie admits that she did not know, but Gladion admitted he knew of a way. The two went on Silvally, out of the mansion. The next day, they arrive to Poni Island. they find an old door with statues of Rowlet, Litten, and Popplio in front of it. Lillie believed it was a puzzle that they had to solve by pushing the statues in place, but Gladion simply pushed the door open. He assumed it was a trap, and had Silvally push the Popplio statue in place, which revealed a spike trap. Gladion ordered Lillie to be careful and not touch anything. They came to a steep cliff, where Lillie thought there was an invisible bridge connected to the other side, and drops some sand in order to find it. Gladion doubted her, telling her to get on Silvally, as they leapt away. He informed her Lillie that there was a bridge, but was destroyed a long time ago. Lillie started thing she was slowing her brother down, but decided to continue. Gladion knew that Lillie won't stay put even if he told her, and the two proceed forward. They came to an old ruin, where a group of Jangmo-o, Hakamo-o, and their leader Totem Kommo-o ambushed them. Lillie sent out Snowy to battle the Jangmo-o, and Hakamo-o while Gladion and Silvally deal with Totem Kommo-o. Totem Kommo-o's hard scales were too hard for Silvally's Crush Claw, and Totem Kommo-o did not take much damage. Lillie advised Gladion that if Silvally could change into a Fairy-Type, they might be able to beat Totem Kommo-o. Gladion was to equip Silvally with a Fairy-Type Memory Disc, but a Jangmo-o disarmed him and the Memory Disc landed underneath Totem Kommo-o. Lillie and Snowy created a path by attacking the Jangmo-o and Hakamo-o and freezing the ground with Powder Snow. Gladion and Silvally skated across the frozen floor while Totem Kommo-o charged up a Clanging Scales attack. Gladion retrieved the Memory Disc and equipped Silvally, protecting the two from Kommo-o's attack. Silvally defeated Totem Kommo-o with a Multi-Attack; Lillie congratulated her brother, but Gladion gave the credit to Lillie. The ceiling began to crumble down on them, so the siblings rode on Silvally to reach the exit, and were saved from a falling rubble by an Electro Ball. After they barely make it out to the Altar of the Sunne, Ash and his classmates, along with Professor Kukui, came out, too. Gladion reminded Ash that was a family situation, but Ash reminded that people in Alola shared everything, including family situations. Persuaded by Lillie that they could use all the help they need, Gladion permitted them to stay. Suddenly, everyone saw as the Guardian Deities of Alola showed up for an important meeting.
The group encountered the Guardian Deities, and asked them to lend the power to open an Ultra Wormhole, since Gladion reminded they were to meet Solgaleo at the place. Gladion watched as the Guardian Deities showed a screen presenting Nebby's creation, and how Ash found it. Gladion became impatient, since they had to save his mother, but Lillie thought they should wait what the Guardian Deities had to show. The Guardian Deities performed a ritual, which caused Nebby to evolve into Solgaleo, which astounded the group. In addition, the Guardian Deities upgraded Ash's Z-Ring, giving it a different slot, and black color. Gladion went on Solgaleo, who opened an Ultra Wormhole to cross into the another dimension.
The group arrived into the Ultra Space, where they soon found a bunch of Ultra Beasts, UB01: Symbiont, floating around. The group was to search for Lusamine, who touched Sophocles. They saw Lusamine darker, fused with the Ultra Beast, floating around, and screamed they stayed away from her. Lillie ran to her mother, forcing Ash and Gladion to go after her. Lusamine blocked the way with boulders, so Ash protected Lillie while Gladion's Umbreon destroyed the boulders with Dark Pulse. Gladion believed UB01: Symbiont was the cause of Lusamine's strange behavior, and feared it was draining her energy. Lusamine floated away, leaving behind a trail of boulders wherever she went. The children used that trail to follow her. Gladion thought that part of her real personality was being shown, because of her life-long dream to meet an Ultra Beast, which made Gladion believe Lusamine wasn't aware she's being controlled. Lusamine started sending Pokémon, so Gladion split with the group to let Ash, Pikachu and Solgaleo advance on to confront Lusamine. Gladion, his Lycanroc, Umbreon, and Silvally faced Absol, who used Ice Shard on Silvally's feet, as well as Mean Look on Lycanroc and Umbreon, immobilizing them.
With all three of his Pokémon immobilized, Absol continued to attack them. Gladion equipped Silvally with a Fire Memory Disc, changing it into a Fire-Type Pokémon. Silvally broke free from the ice, and with Absol distracted, Gladion had Lycanroc use Continental Crush to defeat it. However, Absol was restored to its health, due to the Ultra Beast energy powering it up. Gladion realized until UB01 was defeated, this fight would continue on; he left Lycanroc and Umbreon deal with Absol, and rode off on Silvally. Gladion met up with Lillie, Snowy, Ash's Lycanroc, and Lusamine's Clefable, whom Lillie managed to free from the Ultra Beast's control, while Ash, Solgaleo and Pikachu were facing Lusamine across the toxic goo. Gladion informed Ash of the situation, and was worried about the others. Lillie went atop Clefable, who was protected from the toxic goo with Magic Guard ability, while Gladion equipped Silvally with a Steel-type Memory Disc to make it immune to that. Lusamine rose up, creating a mountain of rocks. Lillie went to talk things over with her mother, and managed to snap out of her state. However, the Ultra Beast refused to let Lusamine go and made her attack Lillie, who was saved by Gladion and Silvally. Thr Ultra Beast grew bigger and covered itself with more rocks and spikes, making Gladion believe UB01 was as interested in learning about humans as was Lusamine about Ultra Beasts. Ash wanted to use a Z-Move with Gladion, who already had Lycanroc use Continental Crush against Absol. Instead, Gladion and Lillie distracted Lusamine to let Ash have Pikachu use a new Z-Move, which was 100 times stronger than Thunderbolt. The powerful Z-Move defeated the Ultra Beast, allowing Lillie and Gladion to pull their mother out of it, who was unconscious and covered in black ink. While the Ultra Beast fled, Lusamine woke up, causing all of her Pokémon to stop the battles with the rest of Ash's classmates. Gladion and Lillie help their mother stand up, and Lusamine apologized to them. Gladion watched as his sister cried in her mothers arms, relieved mother has snapped out of her state. The group came out of the Ultra Wormhole by riding on Solgaleo, pleasing Kukui and Burnet for their arrival. However, Gladion was not glad to see that Sophochles has brought a rock from the Ultra Space. In the end, Lillie, Gladion and Lusamine took a helicopter to Aether Paradise.
The night before Professor Kukui and Burnet were getting married, Ash and Pikachu were greeted by Gladion and his Umbreon. Ash invited Gladion to the wedding ceremony, Gladion replied Ash he was going on a journey, due to his amazement of the Z-Move Ash and Pikachu did in the Ultra Space. Thus, Gladion swore to do the Island Challenge, and asked of Ash to congratulate Professor Kukui and Professor Burnet for him. As Gladion left, Ash promised to him that he'll continue his Island Challenge too, and offered to challenge him to another battle someday, causing Gladion to smiled and waved goodbye.
Later, Ash remembered Gladion and his Type: Null during his battle against Nanu and his Krookodile when Lycanroc's fur got dirty after being hit with Sand Tomb and Mud-Slap.
Sometime later, Silvally started acting restless as it sensed the Ultra Beast's presence. Gladion calmed it down and assumed that something is definitely wrong. Thus, Gladion, wearing a new suit, came to Altar of the Sunne to join the Ultra Guardians. He was slightly alerted of Ash's Poipole, who was an Ultra Beast. Regardless, to find the Ultra Wormhole that caused distress, the Ultra Guardians, including Gladion, had their Z-Moves launched at Faba's machine, which cleared the skies. While the scientists were researching, Lusamine showed a ruin inside the altar, showing the Radiant One. She believed the mystery could be solved if they could decipher the ancient code. Suddenly, Wicke called everyone to come back, as everyone saw Lunala emerging from the Ultra Wormhole with a dark Ultra Beast.
To find more out, the Ultra Guardians pursued the Ultra Beast that chased Lunala. Gladion had his Ultra Guardian Pokémon, Noivern, fire Boomburst at the Ultra Beast, which only made the latter mad and emitted lasers. Lillie fell down from her Altaria, but was saved by Lunala. Since the Ultra Beast was dangerous, the Ultra Guardians halted their attacks, and saw as the Ultra Beast equipped itself to Lunala. Gladion tried to have his Noivern use Boomburst and Bite, but the Ultra Beast attacked him. Gladion fell off Noivern, but Ash saved him. Solgaleo, known as Nebby, appeared, and attacked Lunala, causing it to defuse with the Ultra Beast, but due to its injuries, it fell down on a beach. An electric net electrocuted Nebby and Lunala, but Gladion and Ash had Silvally and Pikachu free them. In the moment of distraction, the Ultra Beast equipped itself to Nebby and vanished through the Ultra Wormhole. The Ultra Guardians went to their base, where Lunala was recovering. Gladion asked his mother about the Ultra Beast, who did not know much about it, and codenamed it as UB: Black. The Ultra Guardians decided to team up with Lunala and save Nebby, for Gladion wanted to repay Lunala for saving his sister and Nebby for rescuing his mother. Just then, the Z-Rings glowed, as Lunala was restored to full power.
The adults came in to see what happened, and the Ultra Guardians informed them they wanted to go through the Ultra Wormhole to save Nebby. Lusamine refused to have them travel through the portal, since it was dangerous, but Gladion reminded they did go to the Ultra Beasts' world to save her. Lusamine saw his point, and let the group save Nebby. After travelling through the Ultra Wormhole, the Ultra Guardians entered a strange dimension that used to be the home of Ash's Poipole. As they searched for the Ultra Beast, they were attacked by wild Poipole; Ash's Poipole stopped them and told them they're not villains. Gladion tried to stop his teammates, since they'd lose track of Lunala. Ash refused, and just then, an old and weak Ultra Beast, reminiscent of Poipole, came out and the Ultra Guardians rushed over to help it. Gladion listened to the Pokémon's story, and learned that if they were to stop the Ultra Beast, named Necrozma, who was the Radiant One that lost its light, Poipole's world would be enveloped in darkness. Suddenly, the gang heard a crash outside and saw Lunala still fighting with Necrozma, who was still fused with Nebby. Gladion and Silvally attempted to defeat Necrozma, but they were immediately stopped by their teammates, who didn't want either side to suffer. Gladion stood down, and saw the battle between Necrozma and Lunala raging on. To try defusing Necrozma from Nebby, Ash, Gladion Kiawe, and Lana had their Pokémon fire their Z-Moves at Necrozma.
The attacks only made Necrozma stronger, who fired lasers that blew away the group. The group stood back up, and despite having no plan, Ash swore he'd never give up, and the group supported him. The group was contacted by Lusamine and the scientists, who explained that Necrozma needed more power. Since the Ultra Guardians fired their Z-Moves, Burnet explained it needed the power of Pokémon and people, for they, too, were involved in restoring Necrozma ages ago. The Ultra Guardians and their Pokémon made a pose, and shared some of their Ultra Aura to Necrozma.As well as every Human and Pokémon, and the Island Kahuna's Z-Power. They managed to have Necrozma diffused from Nebby, but the former still craved for more power. To protect Nebby and Lunala, Gladion had Silvally use Air Slash to prevent Necrozma from reaching them. As a final measure, Gladion, who received the Z-Crystal from Lunala, passed the Z-Power to it. Along with Ash passing his power to Nebby, he and Gladion had the two Legendary Pokémon use Menacing Moonraze Maelstrom and Searing Sunraze Smash at Necrozma. Necrozma gained the power of these moves, and was restored, its body glowing and restored Poipole's world. With the mission successful, Gladion and others went through the Ultra Wormhole, but left Poipole behind. They return to Alola to see Ultra Necrozma appearing before them before it faded into light.
Gladion is a pale young boy with yellow hair and green eyes. His hair appears to be cut into squares and is styled for his bangs to perpetually obscure one of his eyes. He wears a grey hooded shirt with a red decoration on it, some black slashed sleeves, slashed black pants and red shoes with grey soles and black laces. He also has a red rectangular bag around his waist. In addition, he also wears a red-brown Z-Ring on his left wrist.
When Gladion joined with Ash and the group as Ultra Guardians, Gladion's battle suit was different than Ash's group. He wears a black and dark blue battle suit with a navy blue linings in each elbow and a single red line on the front of his suit to match his red belt. At the back of his belt is gray and black and dark blue knee-high battle boots. He also had an Ultra Guardian badge at the center of his suit.
Gladion is a serious and calm trainer, who is looking for worthy opponents in Pokémon battles for himself. Otherwise, he is a "lone wolf" who avoids meeting with his sister. Despite this, he is noted by others to still have a kind side, shown when he told his sister to take care of her Pokémon. While Gladion does not visit his sister often, he swore to protect her after her encounter with the Ultra Beast Nihilego. Unlike his game counterpart, Gladion is much less grumpy and cynical towards others but has a much harder time accepting help from people and often needs persuasion from his sister Lillie. Most of the time, Gladion expresses very little emotions and speaks softly, but he does occasionally smile, such as when he saw his sister overcome her fear of touching Pokémon once and for all. Another example is when he along with Ash, Lillie, and their Classmates all reacted with shock when Tapu-Koko engulfed Ash's Z-Ring. Much like Kiawe, Gladion is shown to be confident in his abilities as a Pokémon Trainer. Like when Tupp, Zip, and Rapp challenged him to a battle, he confidently send his Lycanroc out to battle their Pokémon with his Umbreon on the line. But he's shown to have a slightly arrogant side, shown when he yelled at the Guardians Deities of Alola out of impatience, and did not back down after Tapu-Koko glared at him to be patient. Before the incident the made Lillie afraid of touching Pokémon, Gladion was shown to much more cheerful and much less emotionally distant from the ones he loves. He even used to play happily with his sister all the time, and was even shown to be quite playful and mischievous at times. But he never shown any of these traits after the incident, as he became more dedicated to protecting Lillie from future incidents. He cares for the well being of Pokémon as well, and is hostile towards people to people who have abused them. This is shown through his interactions with the former Brach Chief Faba, as he covered up the incident behind Lillie's fear, and for putting a Limiter Helmet on the Silvally that saved Lillie from Nihilego. Gladion appears to resent his mother Lusamine, as her obsession with Ultra Beast lead to Lillie's fear of touching Pokémon and for remaining completely oblivious of the fact that Faba continued to cover up the incident for years. It wasn't until Gladion told her personally told her what happened that tragic day, and angerlily pointed out that she should've noticed her sudden strange phobia, causing Lusamine to feel extremely remorseful for everything the experience put Lillie through. After Nihilego's return, Gladion proves he is more than willing to protect his sister from danger, by letting Nihilego take him away before Lusamine pushed him out of the way and got taken instead. Though following her abduction by Nihilego, Gladion and Lillie went through great lengths to get her back home safely. Gladion and Lillie's relationship with their mother seems to have improved after her rescue and safe return. Unlike most of Ash's main rivals, Gladions rivalry with Ash has been mutually respectful from start. After he learned that Ash got a Z-Ring from Tapu-Koko, and had battles with it, Gladion decided to have a battle with Ash to test his strength. Gladion eventually grew to trust Ash after he learned about Type: Null, and after being introduced to Nebby. He even told Ash about the incident that made Lillie afraid of touching Pokémon, and trusted him not to tell her. However, after after Nebby teleport Lillie to where he and Type: Null were and partly remembered the incident and became afraid of touching Snowy again, Gladion angerlily blamed Ash in a fit of rage. Ash even thought that Gladion would attack him during the tounglashing conversation, with Lillie stated that it sounds like something he'd do. AfterAfter witnessing Ash and Pikachu's Z-Move 10,000,000 Volt Thunderbolt, Gladion became much more dedicated to surpassing Ash and started to take on the Island Challenge himself.
- Silvally → Type: Null → Silvally (nicknamed Silvally)
- Eevee → Umbreon ♀
- Lycanroc (Midnight Form)
- Like his video game counterpart, Gladion has many similarities to Ryūko Matoi from Kill la Kill. He shares these similarities with Shadow the Hedgehog.
- All three are associated with the colors red and black.
- All three have allies that work with friendship and defeat alien symbiotes.
- All three are up against a threat which is their parent who uses aliens for their bidding and emotionally and physically abuses them (Ragyo Kiryuin for Ryuko, Black Doom for Shadow, and Lusamine for Gladion).
- All three are related to a character wearing blue and white.
- All three are delinquents.
- Gladion is the only rival to be related to one of Ash's traveling companions.
- Gladion has many similarities with Alain:
- Both are Ash's main rivals in their respective series.
- Both are unique among Ash's main rivals in that their rivalries with him are friendly, whereas his rivalries with Gary, Paul, and Trip were fueled by animosity towards each other.
- They both left on their journeys prior to the start of the series.
- They both rescued an injured Pokemon sometime in the past.
- They both desire to get stronger to protect the ones they love.
- They're both close to a younger female beginning trainer. (Mairin for Alain, and Lillie for Gladion)
- They're both loners.
- They both have a friendly rivalry with Ash, which was mutually respectful from the moment they met him, and they became dedicated to surpass him after witnessing a certain aptitude in strength. (Alain witnessed Ash and Greninja transform into Ash-Greninja, and Gladion witnessed Ash and Pikachu using 10,000,000 Volt Thunderbolt)
- Both are Ash's main rivals in their respective series.
- Gladion is the second Pokémon Trainer with a female Umbreon, the first one is Johanna.