Ash and Serena relationship:Ash accidentally discovers the reason why Serena went on a journey and became his companion. (The kiss was not in the Alternate Alola version) They find out calmly sort things out and remain friends. It should have happened in the first 10 episodes.
Now I will explain the position on Serena and her role in the anime, if she had stayed. I think Serena should have been the second protagonist to travel separately from Ash. She would have her companions and adventures, and Ash would have his. They would always travel in the same region, but would follow different paths.
Alola league Arc:
Z attacks were used in each of the battles.
Result:
Top 8
Ash
Gladion
Guzma
Paul
Ike
Serena
Alain
Sawyer
Ash vs Guzma:
Ash Team:
Heracross.
Kingler.
Swellow.
Greninja
Infernape.
Guzma Team:
Scizor.
Pinsir.
Ariados.
Golisopod.
Masquerain.
Battle:
Swellow defeated Masquerain.
Infernape defeated Ariados.
Pinsir defeated Swellow.
Pinsir vs Kingler ended by Double KO.
Infernape defeated Ariados.
Golisopod defeated Infernape.
Scizor vs Heracross ended by Double KO.
Greninja defeated Golisopod.
Alain vs Serena:
Serena Team:
Delphox
Pancham
Sylveon
Wishiwashi
Pinsir(Mega Evolution)
Alain Team:
Unfezant
Bisharp
Charizard(Mega Evolution)
Battle:
Bisharp defeated Sylveon.
Unfezant defetead Pancham.
Delphox defeated Unfeazant.
Bisharp defeated Wishiwashi.
Delphox vs Bisharp ended by Double KO.
Mega Charizard X defeated Mega Pinsir.
Paul vs Gladion:
Paul Team:
Ursaring
Blaziken
Electivire
Honchkrow
Torterra
Gladion Team:
Crobat
Weavile
Umbreon
Zoroark
Silvally(Fighting Memory)
Battle:
Honchkrow defeated Crobat
Weavile defeated Torterra
Zoroark defeated Honchkrow
Blaziken defeated Weavile and Umbreon
Zoroark defeated Electivire
Blaziken defeated Zoroark
Ursaring defeated Silvally
Ike vs Sawyer:
Sawyer's Team:
Sceptile.
Salamence.
Aegislash.
Clawitzer.
Mudsdale.
Ike's Team.
Incineroar.
Swampert.
Golem.
Togekiss.
Druddigon.
Battle:
Golem defeated Salamence and Aegislash.
Mudsdale defeated Golem.
Clawitzer defeated Druddigon.
Incineroar defeated Clawitzer.
Mudsdale defeated Togekiss.
Incineroar defeated Mudsdale.
Mega Swampert defeated Mega Sceptile.
Top 4.
Ash vs Alain.
Ash's Team:
Pikachu.
Greninja.
Hawlucha.
Noivern.
Talonflame.
Kommo-o.
Alain's Team:
Charizard
Tyranitar.
Weavile.
Bisharp.
Unfezant.
Metagross.
Battle:
Noivern defeated Unfeazant.
Hawlucha defeated Bisharp.
Tyranitar defeated Noivern.
Talonflame defeated Weavile.
Metagros defeated Talonflame.
Charizard defeated Hawlucha.
Kommo-o defeated Tyranitar.
Metagross defeated Kommo-o and Pikachu.
Greninja defeated Metagross.
Ash-Greninja defeated Mega Charizard X.
Ike vs Paul.
Ike's Team:
Hitmontop.
Crobat.
Slaking.
Aurorus.
Swampert.
Incineroar.
Paul's Team:
Blaziken.
Electivire.
Ninjask.
Hariyama.
Nidoking.
Drapion.
Battle:
Ninjask defeated Crobat.
Slaking defeated Hariyama.
Blaziken defeated Slaking.
Swampert defeated Ninjask and Nidoking.
Drapion defeated Hitmontop.
Aurorus defeated Drapion.
Electivire defeated Aurorus.
Incineroar defeated Electivire.
Mega Swampert defeated Mega Blaziken.
Finale:
Ash vs Ike.
Ike's Team:
Trevenant
Steelix
Dragalge
Medicham
Swampert
Incineroar
Ash's Team:
Pikachu.
Charizard.
Sceptile.
Infernape.
Krookodile.
Greninja.
Battle:
Infernape defeated Steelix.
Trevenant vs Krookodile:Double KO.
Sceptile defeated Medicham.
Incineroar defeated Infernape.
Dragalge defeated Sceptile.
Charizard defeated Medicham.
Dragalge defeated Charizard.
Pikachu defeated Dragalge.
Mega Swampert vs Ash-Greninja:Double KO.
Pikachu defeated Incineroar.
Champion vs Champion battle:
Ash vs Cynthia.
Ash's Team:
Staraptor.
Torterra.
Infernape.
Buizel.
Gliscor.
Garchomp.
Cynthia's Team:
Spiritomb.
Roserade.
Togekiss.
Lucario.
Milotic.
Garchomp.
Battle:
Buizel defeated Spiritomb.
Roserade defeated Buizel.
Gliscor defeated Togekiss.
Staraptor defeated Roserade.
Lucario defeated Staraptor.
Milotic defeated Gliscor.
Ash's Garchomp defeated Lucario.
Milotic defeated Torterra.
Ash's Garchomp defeated Milotic.
Cynthia's Garchomp defeated Ash's Garchomp.
Infernape defeated Cynthia's Mega Garchomp.
Ash's Birthday.
At Ash's birthday party, all his friends gathered. He learns how their life has turned out after the end of the journey with him.
Some have achieved their goals, some have not yet, and some have just started their journey as a Pokémon Trainer.
Ending: Ash meets Leon. After a battle with him that ended in a draw, Ash decides to enter the World Coronation Series and embarks on a new journey, Serena decides to go on her own journey.
