Kieran

Introduction

Kieran is the rival character of both Pokemon Scarlet and Violet DLCs, the Teal Mask and the Indigo Disk. Kieran is notable for being the first rival in the main series to have a negative character arc, starting off as friendly before becoming aggressive to the player.

Personality and story

Kieran is initially a very shy and meek boy. The player is his first true friend, and he finds himself very attatched to them despite only knowing them for a few days.
Kieran's feelings towards the player turn bitter when they hide the fact that they met Ogerpon, the Pokemon that Kieran is somewhat obsessed with, from him. The player only hid this because his sister requested that they do so not to break his heart, but Kieran doesn't know this, so he assumes they were hiding it out of spite.
When he finally meets Ogerpon face to face, the Pokemon seems more interested in the player, presumably due to having met them first. This enrages Kieran, and he demands to battle the player to see who keeps Ogerpon for themself against Ogerpon's own wishes. Kieran loses and runs off in tears, refusing to see the player off when they leave Kitakami.
The next time the player sees Kieran, now at the Blueberry Academy in Unova, he has a new hairstyle and outfit to match his new attitude. He has begun to bully students he deems "unworthy" out of the League Club, which he has since become the Champion of.
Drayton, the former Champion and now Elite Four member, somewhat uses the player in order to get his revenge on Kieran. He gets them into the League Club so that they can defeat the Elite Four (including him) and by extention, Kieran. When the player does eventually get to Kieran,they defeat him, which causes him to break down. Drayton taunts him, calling him the "ex-champion," but not without encouraging him to stop being so rude to others and to go back to how he used to act. Kieran doesn't listen, vowing to take down the player, even if he couldn't this time.
Kieran, desperate for a way to one-up the player, goes on a trip to Area Zero with Carmine, Briar, and the player themself, in order to catch the mysterious Pokemon Terapagos, reasoning that catching a powerful Pokemon will give him what he needs to defeat them.
Kieran eventually does catch Terapagos- using a Master Ball on it. Terapagos, apparently, was not happy about this- because when it terastalizes, it refuses to go back into the Master Ball- breaking it and firing a beam of energy at Kieran. The player and Koraidon/Miraidon step in, stopping it from hurting him. Carmine and the player take on Terapagos, but Carmine only has one Pokemon left, which swiftly goes down. Carmine begs Kieran to help, eventually getting through to him. He helps the player defeat and catch Terapagos.
When they return to the academy, Kieran profusely apologizes to the player and asks if they can start over and be friends again. The player presumably accepts.

Pokemon Used

Kieran uses many Pokemon, often switching them in and out of his team. Those Pokemon include: Yanmega, Furret, Poliwrath, Gliscor, Cramorant, Shiftry, Probopass, Dragonite, Politoed, Porygon-Z, Grimmsnarl, Incineroar, Hydrapple, and Terapagos (which he swiftly loses.)

My thoughts on Kieran

Kieran is absolutely one of my favorite rivals. I've wanted a rival to have a "joker arc" for years- heck, I made my own rival that fits that bill. Kieran's arc is just so good to me. He's clearly, objectively, in the wrong- but you understand his reasoning and how he's thinking. He's a 14 year old going through a phase, and the first person he finds himself truly trusting went behind his back and lied to him about something extremely important to him. I'd be pissed too.
Some people use the Terapagos incident as a reason to call Kieran a bad person- but I think that his reasoning for that also made sense, even if it was a terrible idea. He was being egged on by Briar, the one adult in the room. If an authority figure I trusted told me to do something that I thought could give me a chance to get revenge on the person who put me through so much pain, I'd proably do it too.
In conclusion: KIERAN NUMERO UNOOOO

Kieran Trivia

- Kieran's Dragonite has a Tera Type but is not coded to terastalize, meaning it is never seen in normal gameplay.
- Kieran is the first main series rival to have a negative character arc. The award for the first rival to do so, however, goes to Paulo from Pokemon Masters EX- who, coincidentally, wrapped up his villain arc about a month before the release of the Teal Mask.
- Kieran is not the first NPC to be seen using a Master Ball, but he is the first NPC to be shown catching a Pokemon with said Master Ball.
- Kieran gives an Applin to the player in a trade. In Galar, giving someone an Applin is used as a confession of love. Take that as you will.
- If you look closely, Kieran has tears in his eyes when throwing out his Pokeball during the Terapagos battle.