Aren't there like three threads exactly like this one?
<Normal Logical Common Sense Mode>
Round 1
Ash vs Alan
Cynthia vs Diantha
Iris vs Lance
Leon vs Steven
Kalos runback, hags, dragons, actually shows Leon's strength against someone who everyone considers truly strong and doesn't feel like he's punching down.
Ash vs Cynthia
Leon vs Iris
Over a decade in the making, shows there's still ways to go for Iris overall, maybe makes Ash wants to win even harder for the sake of Iris.
Ash vs Leon
Duh.
Also, Kalos Team, DP team and PM Team for Ash respectively.
<Fun Mode>
I'll be reposting these greentexts.
>Diantha beats Lance
>Cynthia beats Iris
>Ash beats Steven
>Leon loses against Diantha
>Ash loses against Cynthia
>Ash and Leon meet outside the stadium
>"Leon I lost"
>"Ash I lost"
>they look into each other's eyes for a moment and then burst out laughing
>"our journey is just beginning, there are still so many strong people out there, so many other pokemon to discover"
>Diantha vs Cynthia
>Ash vs Leon (unofficial match)
>outcome: unknown
>THE END
or
>Diantha vs Cynthia finals full of sakuga
>Leon has an all-out battle against Ash in an empty stadium with no outcome shown
>final shot is just Leon and Ash in the ground panting and smiling about what a great battle it was
>SV preview
Or...
They go for a don't count your eggs before they hatch kind of thing where Ash loses to Cynthia because he's unable to see what is in front of him and is too hyperfocused on Leon and afterwards Cynthia beats Leon after getting a waku waku power-up from her fight with Ash making her not want to retire.