This is what happens if you violate the rules of the Pokemon Video Game World Championships
Boring and Unfairly Strong Legendary Trainer
J. Michael Tatum (English) Hiroki Takahashi (Japanese)
Media of origin:
Pokémon the Series: Diamond & Pearl
Tobias (Japanese: タクトTakuto) is a recurring character who appeared in the Pokémon anime. He is a Pokémon Trainer who competed in the Lily of the Valley Conference. He made his debut appearance in League Unleashed!. He was widely hated by the Pokémon fans for winning the league by cheating and letting Ash remain a loser, and is considered as one of the worst characters in the anime.
Even among the trainers who eliminate Ash from official tournaments, Tobias really stands out in how hated he is.
Unlike most, if not all of Ash's rivals, Tobias has extremely little buildup before his battle with Ash, only appearing in a few cameos. Some foreshadowing would have been helpful.
Perhaps the main reason as to why Tobias is so hated is when he officially battled, Tobias wins 6-2 over Ash, using only Darkrai and Latios, a Mythical and a Legendary Pokémon, respectively. How the heck was he able to obtain both Pokémon, and why were they allowed into the league? There isn't even any explanation as to how he obtained those Pokémon or if he used any normal Pokémon in order to do so, or how he was able to find them before entering the league.
In fact, only Elite Trainers have been seen with those Pokémon, so basically, Tobias shouldn't even be allowed to use either of those Pokémon in the battle.
Also unlike most of not all of Ash's rivals, Tobias doesn't even have much of a personality. He nothing more than a basic calm villain with a Sergeant-like personality.
There is little to no reason as to why Tobias is in the Sinnoh League, he doesn't even say as to WHY he's in the Sinnoh League. His main, and possibly only purpose seems to be eliminating Ash, and nothing else. Tobias was most likely only used in the Sinnoh League to defeat Ash, which is plain cruel.
Tobias' battle with Ash is a primary example of the Diabolus ex Machina trope. Since Ash was storming through the league, even having the ability to take out the seemingly invincible Darkrai and the random Latios, he possibly would have won the league. But, since he was never usually supposed to win an official league, Tobias was unexpectedly written into the league as a Juggernaut with a broken Pokémon team just so that Ash wouldn't win and the anime could dump Dawn and Brock and get to the Black & White season faster, which is very lazy and relatively unfair writing.
Tobias never faces consequences for utterly overpowering poor Ash with both a Mythical and a Legendary Pokémon, nor does anyone call him out for that reason, and do you know what that means? He's a Karma Houdini.
Interestingly, there is a plot hole, he could have been kicked out of the battle for violating the rules of the Pokemon Video Game World Championships by using a Mythical and a Legendary Pokemon, though it makes sense since the 2010 have that distinction of using those Pokemon.
Tobias has a polite and honorable demeanor, commending Ash on defeating Darkrai and showing good sportsmanship throughout at the end of the battle.
Tobias' battle with Ash helped to show the true power and potential of Ash's Pokémon, especially Gible, Sceptile and Pikachu.
Given that Tobias won the Sinnoh League this basically allowed him to challenge the Elite Four and Sinnoh Champion Cynthia. However, Cynthia was later revealed in Journeys to have still kept her title as Champion, implying that she either beat Tobias offscreen or that Aaron, Bertha, Flint, or Lucian of the Elite Four managed to beat him.
Tobias' name in the original Japanese version of the anime, Takuto, is a possible reference to Takuto Itagaki, who was the TCG Champion in the Senior Division of the 2009 Pokémon World Championships.