Gladion Hidaka

Gladion Holo'oka'a Hidaka is from Hau'oli City on Melemele Island in the Alola region. He's a member of the Tekiyoku, a Fairy Manipulator. His contract Pokémon is unknown.

He's the older brother of Lillie Hidaka and the son of Lusamine Hidaka and Mohn Hidaka.

Background
Gladion grew up in Hau'oli City with his mother, Lusamine, his dad, Mohn, and his little sister, Lillie. He always defended Lillie when she was getting picked on. He made her feel better throughout various problems she faced in life. The two were close as brother and sister, and she heavily depended on him when she needed guidance. Gladion was said to exude positivity and seemed to make any area "shine" around him, earning him the moniker, the "Golden Sun". Lillie wasn't as outgoing as him, but the two complemented each other well, so Lillie was called the "Silver Moon".

As time went by, Gladion started having a change in his personality. He became involved with ill-mannered people and got into trouble. He rebelled against his mother and father, not following their orders. Somehow, he even became friends with some members of Team Skull at the time.

When Gladion was 15, due to his Team Skull friends, he heard news of Lysandre when he was recruiting villainous teams to join the Tekiyoku. After consideration, he packed his bags and was about to sneak out of the house one night. Lillie was there, who asked what he was doing. He said he was joining the Tekiyoku, but didn't say why. Lillie begged him to stay, but Gladion left anyway and didn't see his family for a while.

Over 2 years later, Gladion, 17 at the time, was in Alola when Tekiyoku members were terrorizing Hau'oli City. He showed up without warning when some of them were beating up his father. Lillie was out there, having been trying to stop them. Gladion walked up, told them to move aside, ignored Lillie, and approached the enemies surrounding his father. He then killed his own father right in front of his little sister. As Lillie cried over her father's body, Gladion left the area and hasn't seen his family since then.

Present
Gladion hasn't debuted yet. He's been mentioned so far first in Episode 32 when Lillie explained the deepest parts of her backstory to Ash. She mentioned everything that Gladion did, as outlined in the Background section. She stated that she and Lusamine have forgiven him by now. Lillie's eyes got teary after saying this, as she begged Ash to help bring Gladion back home.

He's mentioned more in Episode 36 when Lillie told Ash about how kind Gladion used to be. He was so kind, he used to be called the "Golden Sun", whereas Lillie was called the "Silver Moon". Ash resolves to speak to Gladion himself before any decision is made on whether Gladion should return to Lillie and her mom or not.

Personality
What's known about Gladion's personality has been mentioned by others so far. Alain first mentioned that Gladion has a bad attitude, similar to himself and Paul.

It's clear that he's a sinister and twisted individiual to have turned his back on his entire family to join the Tekiyoku. What's even a bigger expression of this is when he returned, only to kill his father. Whether he'll return to Lillie and his mother remains to be seen.

Lillie
Despite how he turned out, Gladion was actually a nice, caring individual who cared deeply about his little sister, Lillie. This happened in their younger days. He defended Lillie from those who picked on her. The two shared a deep bond that Lillie treasured.

It's not clear how he feels towards her at this point, since he completely ignored Lillie when he returned on the day he killed their father. In addition, he never told Lillie why he left to join the Tekiyoku in the first place.

Naming

 * His first name, Gladion, is his name in the English dub of the Pokémon anime. It's similar to his Japanese name, グラジオ Glazio, which is meant to come from "Gladiolus", a perennial flowering plant in the iris family.
 * His middle name, Holo'oka'a, was randomly selected from a Hawaiian name generator.
 * His last name, Hidaka, is shared with Lillie's last name. This was first selected by Nocturnal Jay for Lillie. It roughly translates to "high sun in the sky".

General

 * His birthday, May 18th, is the original Japan air date of the episode of the Pokémon anime he debuted in.