While writing, I am afraid I maybe plot biased, i.e Ash biased.
Sorry I couldn't make it as big as the post above me :3
Round1 (6 on 6)
Battle 1: Ash versus Virgil
Ash: Ash is notorious for jumping into a battle with 0 or no strategy. However what he lacks in the strategy department, he makes it up in the tactics department.
Virgil:Virgil's true talent lies in switching his Pokemon constantly, use his diverse team and has excellent judgement.
First half of the battle.
Assuming they begin with their first Pokemon...
Pikachu versus Eevee.
Eevee is a very troublesome opponent to Pikachu. With its excellent agility and ability to use Dig it troubles Pikachu a lot. But despite this, Pikachu will thanks to its tenacity, experience and a bit of Ash's moves like counter shield, using Iron Tail on the field, blasting the field with thunderbolt(Elesa's Gym.) Pikachu will barely win and won't have much health left though.
Pikachu versus Umbreon
Virgil choses Umbreon to counter the weakened Pikachu. Umbreon will feature Dark Pulse, Protect, Moonlight and Iron Tail. Pikachu will have a hard time beating it and eventually lose. And because Virgil's the badass he is, he will switch out.
Ash and Virgil send out Pokemon simultaneously.
Charizard versus Espeon
With his best partner going down, Ash decides to shake up some momentum by sending his most reliable partner, Charizard. Virgil sends out Espeon. Virgil acknowledges the threat Charizard is. But he manages to constraint the pseudo dragon with Psychic and toss it into the dirt and quickly switches to Vaporeon.
Charizard versus Vaporeon
Uberzard is strong and overpowers Vaporeon, but Vaporeon has good resistance and causes Charizard intense damage with Hydropump. Charizard switched out. Ash realizes forcing with power doesn't work. virgil switches out Vaporeon too, guessing Ash's next Pokemon (as they are revealed below?) and sends out Glaceon.
Sceptile versus Glaceon
With its incomparable speed, Sceptile defeats Glaceon in a tough battle and wins despite type disadvantage. Enter Flareon. Ash switches to Krookodile.
Krookodile versus Flareon
Krookodile has the type advantage, knows the right moves, but Flareon will be superior with its powerful Fire Blast. Flareon will use the flamethrower in the hole to catch Ash off guard and finish off things with Fire Blast.
Charizard versus Flareon
Charizard makes a return, but is severely injured by Jolteon plus Espeon. Flareon and Charizard will have a fire versus fire battle. Charizard cinches the victory, being the badass overpowered pseudo-dragon he is.
With the first half done, Virgil and Ash will evaluate the situation. Ash has lost Pikachu and Krookodile and Charizard is on the verge of going down. Sceptile was slightly damaged but was mostly in good condition. Virgil lost Eevee, Glaceon and Flareon. Espeon avoided damage, Umbreon was injured by a few of Pikachu's attacks, Vaporeon was largely at full health.
Gliscor versus Umbreon
While Umbreon continuously annoys with Protect followed by Moonlight, Gliscor will be successful at avoiding Umbreon's Dark Pulse and Iron Tail. At one point Gliscor will gain momentum (after a critical hit from Dark Pulse) and uses consecutive X-Scissor and Giga Impact, a 2 Combo attack to finish off Umbreon. Even with high defense and healing ability, Gliscor's combo move that involves using its tail as a spring and use two attacks in quick succession finishes the match. Ash switches out Gliscor.
Sceptile versus Espeon
Once again, Sceptile uses its superior speed but Espeon with its Psychic sensory abilitities will put Sceptile on a hold. But at one point after repeated tosses by Psychic and fast attacks from Psy Beams and what not, Sceptile manages to critical hit with a double leaf blade and gets its second victory in the battle.
Sceptile versus Vaporeon
With a type advantage, Ash is sure that he will win. But Aurora beams proves fatal to a tired Sceptile.
Gliscor versus Vaporeon
Gliscor lands a Giga Impact, but is promptly Hydropumped immediately after it.
Charizard versus Vaporeon
One hit KO as Charizard is tired.
Heracross versus Vaporeon
An epic battle unfolds. Vaporeon and Heracros damage each other with Hydropumps and Mega Horns. In a fast action paced and powerful move exchange filled battle, Heracross ultimately wins the battle.
Pokemon of the match goes to Sceptile for being a badass and wreck Virgil's team while Charizard gets respect points for taking the most damage. Krookodile being a disappointment, Gliscor being consistent and Pikachu being Pikachu and Heracross being the awesome game finisher.
Match 2: Tyson versus Paul.
Paul: Excellent strategist, and immensely powerful Pokémon.
Tyson: Amazing battle tactics and techniques and vicious Pokémon.
Meowth versus Torterra
Meowth has a move set of: Slash, Iron Tail, Thunderbolt, and Double Team.
Torterra: Giga Drain, Stone Edge, Frenzy Plant and Crunch.
Predictable. Meowth makes athletic moves and slams Torterra with Iron Tail and does laughable damage with slash. Torterra can’t hit back but is not taking much either. Realizing the futility, Tyson withdraws Meowth.
Metagross makes massive attacks, which even Torterra will be finding difficult to take. But despite that Torterra will survive a Meteor Mash, followed by a Hammer Arm and retaliate with a Frenzy Plant causing intense damage to Metagross. The beastly battle of defense and immense attack power is ended with Paul immediately switching after Frenzy Plant.
Metagross versus Electivire
The lack of Magmortar in his team will be unnerving to Paul. He wishes he had it, but he doesn’t have any choice. Electivire will have: Wild Charge, Protect, Thunder, Cross Chop.
Electivire protects against Meteor Mashes and Hyper Beams and paralyze Metagross with Thunder. But Metagross will use Psychic to control it when Paralyzed. Despite that Electivire survives a Psychic, and retaliates back with Cross Chop, putting Metagross down to the count. Paul’s Pokémon are beasts, because taking a Metagross without losing a Pokemon is a great feat.
Shiftry versus Electivire
Paul tries to use a similar strategy like using Thunder on the field, but Shiftry proves faster and is amazing at dodging. It finishes off Electivire with a timed Dark Pulse.
Shiftry versus Drapion
Tyson, not knowing Drapion’s beastality makes a folly. He tries to use his usual strategy, but Drapion holds it in a bind and poisons it with Poison Fang, and while Shiftry tries to recover, it uses Toxic spikes. Shiftry attacks with a powerful Focus Blast, that does severe damage to Drapion. Drapion promptly defeats it with Pin Missile.
Hariyama versus Drapion
Hariyama finishes off Drapion pretty easily as the damage from Shiftry was too much for Drapion. Hariyama is severely poisoned.
Hariyama versus Torterra
Paul uses his defensive Pokémon on purpose, so that he could let the poison do the work. Hariyama inflicts some damage to Torterra, but the beast has a ton of health and saps Hariyama’s bulk with Giga Drain. Tyson is severely in trouble.
The first half ends. Tyson lost Metagross, Hariyama and Shiftry. Meowth was almost at full health but was briefly hit by Stone Edge from Torterra. Paul has Torterra at a reasonable amount of health thanks to sapping off Hariyama’s health. He lost Drapion and Electivire but had Toxic spikes to his advantage. Either sides have already used their strongest Pokémon right at the beginning of the battle.
Donphan versus Aggron
Metal Sound and poison damage with Flash Canon to add to the pain. And top off it Aggron easily counters any of Donphan’s physical attacks with Iron Head. The final attacks between them would be Superpower versus Double Edge. Donphan wins but is basically out of the game.
Sceptile versus Ursaring
Tyson can’t use his usual tactic: Detect thanks to the poison but his Sceptile is still powerful. In a heated battle, Sceptile falls but with its Overgrow finishes off Ursaring with Solar Beam.
Sceptile versus Honchkrow
Honchkrow plays its boss role by crushing Sceptile with ease. Flying type+ Poison damage proves fatal to Sceptile. It could have won if it had used Detect, but the poison….
Meowth versus Honchkrow
Meowth is poisoned but jumps onto Honchkrow and t-bolts it to death.
Meowth, Donphan versus Torterra
Meowth puts up a reasonable battle, but Torterra’s defense and Toxic spikes are not friendly to Tyson at all. The battle ends. Donphan is one shotted by Frenzy Plant in a shattering loss. Paul wins with his beastly Torterra still standing.
Battle 3: Gary versus Cameron
Gary: Smart, raises Pokemon pretty well. Not an excellent strategist or tactician but better than Ash at strategy Cameron:Dumb and smart. Depends on whether he pulls his head band or not.
Blastoise versus Lucario
Lucario is strong, tenacious like Ash's Pikachu. But Blastoise is Gary's strongest Pokemon. The battle will be excellent to say the least but Blastoise will ultimately win in this 1 on 1. Blastoise is switched out.
Nidoqueen versus Hydreigon
Another epic battle. Nidoqueen is extremely strong and has the raw power to pull down Hydreigon's horns, but Hydreigon was shown to be brutally strong. Tri Attack, Dragon Rush and Dragon Pulse are overwhelming moves and even Gary's Nidoqueen won't be able to take it but it would deal some good damage before it though.
Scizor versus Hydreigon
Gary expects Scizor to win with its type advantage, but the fire part of Tri Attack proves difficult for Scizor. In an intense exchange of moves, either Pokemon fall down after either side knock each other out simultaneously with Dragon Rush and X-Scissor.
Gary sends out his ultra reliable partner Umbreon while Cameron sends out his starter....
Umbreon versus Samurott
Intense mindless attacking brings the win to Cameron. Razor Shell, Mega Horn, and Hydro Canon.
The first half ended badly for Gary with him losing Nidoqueen, Scizor and Umbreon. But he's at a good advantage because he still has Blastoise while Cameron lost his main two Pokemon.
Electivire versus Samurott.
Cameron doesn't switch, so Electivire gets the prompt win.
Electivire versus Ferrothorn
For once, Cameron won't be an utter moron and use Swanna. Electivire loses to Ferrothorn's sharp attacks and its own inability to hurt it much.
Arcanine versus Ferrothorn
Ferrothorn in fact deals a huge damage and paralyses Arcanine despite the huge type advantage. But Arcanine doesn't take more than one move to finish the match.
Arcanine versus Swanna
Swanna has the advantage and Arcanine was paralyzed on top of it. Brave Bird finishes Arcanine off.
Blastoise versus Swanna
Cameron attempts Brave Bird, Gary punishes his folly with a Single Hydro Canon and OHKOS Swanna.
Blastoise versus Watchog
But despite its epic strength and what not, Blastoise is tired from the intense battling with Lucario, and on top of that Watchog does know Thunderbolt. The match turns into an embarrassing loss for Gary.
Match 4: Harrison versus Barry
Harrison: Experienced Pokemon trainer, has good focus on tactics and uses rare strategies to stump the opponents. Barry:Raises powerful and balanced Pokemon. Is extremely good at pushing the opponent into defense and overwhelms with his offensive momentum, but it could sometimes backfire him.
Blaziken versus Empoleon
Harrison expects Blaziken to overpower Empoleon. With its exceptional jumping skills and moves like Hi Jump Kick, he expects to finish Empoleon quickly. Barry is not so weak. Empoleon cancels out every attempt Harrison throws at Barry and instead corner Blaziken with continous Drill Pecks. Harrison switches out.
Kecleon versus Empoleon
Empoleon makes a quick work out of Kecleon but Kecleon manages to paralyze the Emperor Pokemon with lick.
Steelix versus Empoleon
With a poorly chosen team that is entirely weak to Empoleon, Harrison has no choice but to use Steelix, a ground type to deal Empoleon. But a Hydro Canon in the Hole makes Steelix faint right in midst of its attempt to use Dig. Zero damage to Empoleon.
Hypno versus Empoleon
Hypno puts Empoleon to sleep. Barry switches out.
Hypno versus Heracross
Hypno uses Hypnosis, but Barry who intensely watched Ash in the league pulls out a surprise out of his ass, and uses Sleep Talk. Plot calls out Megahorn and finishes Hypno.
The first half ended poorly for Harrison. He lost three Pokemon and in return did nothing to damage Barry. But he still had his iconic Blaziken. On the other hand Barry has two sleeping Pokemon.
Sneasel versus Skarmory
Skarmory plays around with Sneasel, uses Spikes but gets a frozen wing in return. But a Steel Wing defrosts the attack and finishes off Sneasel,
Houndoom versus Skarmory
Barry switches out.
Houndoom versus Hitmonlee
Houndoom uses Counter, first win for Harrison.
Houndoom versus Staraptor
Houndoom loses to Staraptor despite Counter thanks to damage it already took from Hitmonlee.
Blaziken versus Staraptor.
Blaziken one shots Staraptor with Blaze Kick.
Blaziken versus Roserade
Barry attempts to poison Blaziken but Blaziken is too quick, agile and jumps very well and finishes off with Quick Attack + Blaze Kick.
Blaziken versus Skarmory
Blaziken takes damage from Drill Peck but mashes Skarmory with Hi Jump Kick, followed by Blaze Kick and then flamethrower.
Blaziken versus Heracross.
Finished in sleep. Heracross fails to do any damage.
Blaziken versus Empoleon
Despite mutilating more than half of Barry's team without any difficulty, the fatigue gets to Blaziken but Empoleon is sleeping. Barry goes on with the "I believe in you" screams. Empoleon gets up after taking a Hi Kimp Kick.
Blaziken dodges Hydro Canon and damages with Blaze Kick.
Blaziken and Empoleon make one final move Drill Peck versus Hi Jump Kick. Empoleon wins thanks to Blaziken's exhaustion.
No offense but except for Blaziken and Houndoom, Harrison's team sucks and I think their fate was deserving........and I had to make Barry's Empoleon strong too because he basically overuses it.
Match 1: Ash versus Paul
Pikachu versus Torterra
Pikachu begins with Ash using extremely fast moves and topples Torterra with Quick Attack and smash it into the ground with Iron Tail. Stone Edge is stopped by Counter Shield, Frenzy Plant completely misses the rodent's moves. Paul switches out thanks to Pikachu's uber hax power. Ash switches out Pikachu too.
Heracross versus Ursaring
Ursaring switched out immediately.
Heracross versus Honchkrow.
Heracross switched out immediately.
Gliscor versus Honchrkow
Honchkrow is switched out.
Ash and Paul are pressurizing each other with switches alone. Ash is extra careful in this match than usual because he knows how potent Paul is. But Paul is using Ash's extra carefulness/OOCness to confuse his strategy.
Gliscor versus Aggron.
Ash switches out. Paul switches out immediately.
Sceptile versus Torterra
Ash finally orders to attack. Sceptile deals good damage with Leaf Blade, but Torterra usea Stone Edge which Sceptile dodges with ease, but Torterra keeps controlling the attack till Stone Edge ends up on Torterra's face. Ash is happy, but Torterra uses the slight moment of cockiness by Hyper Beaming all of a sudden. Sceptile is severely damaged and switched out. Torterra is switched out.
Krookodile versus Ursaring
Krookodile launches its Stone Edge but Ursaring counters with Focus Blast, Ash orders Dig, Paul orders Bulk up. Dig doesn't do much. Ash orders Dragon Claw, Paul orders Slash. Slash over powers. Then Paul orders Focus Blast, Ash orders Dig again, Paul orders Hammer Arm on the ground. Krookodile comes out. Ash switches out again. Poor Ash, you shud stick to your style, don't let Paul intimidate you.
Heracross versus Ursaring.
A repeat match up where Heracross had the advantage previously. But the tide of the battle changes with Bulk up. Ursaring finishes off Heracross with Slash and Hammer Arm.
Charizard versus Ursaring
Ash knew he had to stop the raging Ursaring with power. In a monstrous battle, Charizard wins against the beast called Ursaring but is brutally damaged in the process. Charizard is switched out.
Pikachu versus Electivire
The uncomfortable matchup returns and pride is a bitch for Ash. The epic battle ends up with Electivire winning.
Krookodile versus Electivire
Electivire is switched out.
Krookodile versus Drapion.
Krookodile is switched out,
Gliscor versus Drapion.
The match up returns. Gliscor with its new move Acrobatics proves a pain for Paul. Toxic Spikes are stopped by Stone Edge in a brilliant DEM move. Gliscor locks pincers with Drapion, but Drapion uses a move Paul especially taught for beating Gliscor: Aqua Tail. Aqua Tail does damage, but Gliscor retaliates with Acrobatics and Giga Impact. Gliscor finally wins. Gliscor is switched out.
Charizard versus Honchkrow
Charizard is strong, but it had to be Ash's sponge from an Ursaring sweep. And it had reached its limit. Honchkrow was the superior bird and defeats it. Honchkrow barely survives.
Ash lost three Pokemon. Charizard, Pikachu and Heracross. Sceptile was badly injured, and so was Krookodile. Gliscor had a tiring match with a biiig beast like Drapion, it's state was just as sorry. Paul had Honchkrow at low health thanks to Charizard's intense attacks, lost Ursaring and Drapion, two of his main sweepers. Electivire was damaged by many of Pikachu's fast moves and was battered as well. Aggron, Torterra were at full health.
Gliscor versus Electivire
Athletic Gliscor proves to be a beast again, and defeats Electivire with repeated X-Scissor and Acrobatics and a final Giga Impact. Gliscor switched out.
Krookodile versus Aggron
Krookodile wins against Aggron, the beast.
Krookodile versus Torterra
Krookodile switched out.
Gliscor versus Torterra
Gliscor uses Acrobatics and dodges Frenzy Plant, leaving Paul helpless and forced to switch.
Gliscor versus Honchkrow
In a wonderful aerial battle, Honchkrow wins against a exhausted Gliscor.
Krookodile versus Honchkrow
Dig+ Stone Edge. WIN
Krookodile versus Torterra
Sceptile versus Torterra
Final Battle. Torterra is immensely exhausted thanks to Gliscor and Sceptile's previous battle. Sceptile has been struck by Hyper Beam an dis in the verge of going down. Either Pokemon activate Overgrow and get into a powerful meelee. Frenzy Plant is beaten by Sceptile's superb speed and finished off things with Leaf Storm.
The epic battle that should have been the finals ends. Ash wins
Battle 2: Cameron versus Barry
Lucario versus Empoleon
Lucario uses Aura Sphere, Empoleon counters it with Hydro canon. Lucario uses Force Palm. Barry is scared, switches out.
Lucario versus Staraptor
Lucario proves to be the freaking ace it is, Staraptor falls.
Barry is officially mad.
Lucario versus Skarmory
Skarmory wins after taking quite a few hits.
Ferrothorn versus Skarmory
Ferrothorn versus Heracross
Barry wins because Cameron doesn't know what switching means.
Samurott versus Heracross
Samurott wins. Barry lost three Pokemon.
Barry lost three Pokemon. Heracross, Staraptor and Skarmory. Empoleon is in good health. Cameron lost Ferrothorn and Lucario. Samurott is at not so good health thanks to Heracross.
Samurott versus Roserade
Roserade wins thanks to Leaf Storm
Hydreigon versus Roserade.
Roserade uses Poison Jab to poison Hydreigon. Hydreigon demolishes it though.
Hydreigon versus Hitmonlee
Hitmonlee is good but Hydreigon is a beast. But Barry's tactics work and Cameron loses his secret weapon too.
Swanna, Watchog versus Empoleon
Not much to say here. Empoleon is just a beast. Barry wins.
Note: Cameron should learn to switch.
Finals:Ash versus Barry
Pikachu versus Empoleon
Smart Barry switches out.
Pikachu versus Roserade
Poison Jab more Poison Jab. Pikachu is damaged and switched out.
Charizard versus Roserade
Roserade switched out.
Charizard versus Empoleon
Barry's beast who wins him matches regularly versus Ash's strongest Pokemon that saved his fine ass every single match. Charizard wins sadly. I know I hate it too. Charizard is returned.
Heracross versus Heracross
Ash's Heracross cinches the victory in a battle of equals. Heracross is switched out.
Charizard versus Skarmory
Barry proves that guts and strategy, one can always overturn the match. Charizard is exhausted from the epic match with Empoleon. Charizard falls to Skarmory.
Pikachu versus Skamory
Skarmory uses Spikes while Pikachu finishes it off.
Ash lost Charizard while Pikachu managed to defeat Roserade with ease. Heracross was almost down to the count. Barry lost Skarmory, Heracross and Empoleon. His valuable assets were down and Ash still had three more dangerous Pokemon at full health. But he had spikes.
Sceptile versus Staraptor.
This is where Ash begins to make mistakes. Spikes unnerve him as it's his first time facing them. He doesn't know if he has to switch or let his Pokemon die. He did the latter for now.
Gliscor versus Staraptor
Gliscor cinches an easy victory over the bird, but was hurt by Brave Bird in return.
Gliscor versus Roserade
Gliscor is fast, but Roserade has leafstorm.
Heracross versus Roserade
Barry switches out.
Heracross versus Hitmonlee
Monlee wins as Heracross is exhausted.
Pikachu versus Hitmonlee
Hitmonlee is switched. Barry's a smartass.
Pikachu versus Roserade
Plot power activates, Pikachu uses all those techniques at its disposal and get a win.
Pikachu versus Hitmonlee
Hitmonlee and Pikachu's fight. Pikachu uses a Thunderbolt and smashes an Iron Tail on Hitmonlee's face before going down.
Krookodile versus Hitmonlee
Hitmonlee is weakened, but it had immense type advantage. Ash sends out his Krookodile and-
LOL, I feel like a troll now :x
Sorry, for making it such a cliched tournament with Ash winning. But I was personally disappointed with Virgil, Paul, Tyson going down early. The matchups were kinda disappointing but I have to do what the OP wants :3 Hope you had fun reading this.
It took me a whole day to write that. I strictly went with what the OP wanted :3