Max Sp.Atk/Spe; ability Compound Eyesaccuracy-boosted via abilitySleep Powderas setup foothold, Quiver DanceVivillon build raising stats. After putting opponent to sleep, Substituteby preserving it, safely earn action turns while aiming for sweep.

CS Setup Ace Role

benefiting from abilitySleep Powderdisable opponent with it, Quiver Danceraise own stats to dominate as main role.Leftoversrecovers via, Substitutesupplements consumption of it, one-sidedly push high-power Hurricaneplays as an ace.

Threats

Weak to Substitute-piercing moves

Vivillon SubstituteIt fights with it as shield, so piercers like Weak to multi-hits and sound moves. Bulk is also low, so Icicle Spear or Rock BlastBe careful if opponent can use it.

With Speed EVs, Choice Scarf to act before opponents — a support Vivillon.It forces through Sleep Powder, whose accuracy is boosted by the ability Compound Eyes, with priority in turn order, shutting down the opponent's actions to create a board where allies can move safely.

EV Allocation Intent

By raising HP and Def with EVs, it endures the moves of the popular Kingambit's Kowtow Cleave and Mega Gardevoir's Hyper Voice. Additionally, by raising Speed, it can move before Garchomp with the Nature いじっぱり with Choice Scarf as well.

Alternative Move Options

Rain Dance also recommended

If you want to counter Mega Charizard Y, Rain Dance is recommended. Rain Dance sets the weather to あめ状態 and にほんばれ状態 removes it while halving the damage of Fire moves. Furthermore, since Water moves deal increased damage during rain, making your ally a Water-type Pokémon is powerful.

Doubles Scarf Build Role

an opener that controls the board by moving first to use high-accuracy Sleep Powder — its role. Choice Scarf locks its move, but with its ability-boosted accuracy, Hurricane can chip damage, or Rage Powder to protect an ally and pivot out — viable playstyle.

Threats

Weak to Pokémon faster than itself

It is weak to Pokémon faster than itself. Garchomp with the Nature ようき with Choice Scarf, as well as Talonflame and Excadrill that move first via their abilities, are examples. Be sure to include Pokémon on your team that are favorable against these threats.

Speed and Sp.Atk raised, ability-boosted accuracy of Sleep Powder/Hurricane as core hazard setter + special attacker Vivillon.Focus SashLeveraging it to sleep opponents, Tailwindor boost ally Speed with it to shape favorable boards — specialty.

Alternative Move Options

Rage Powder instead of Protect recommended

ProtectInstead of Rage Powderis also recommended. Rage Powder Vivillon takes ally-targeted attacks instead.

Doubles Sash Build Role

Debut as lead or after ally retreat, high-accuracy Sleep Powder seals opponent movesand creates ally-friendly conditions as main role. Self also chips with high power and Speed control reliably supports team setup.

Threats

Weak to Flying and Ice multi-hits

Vivillon struggles vs. Flying/Ice multi-hits. Both are super-effective, multi-hits OHKO even with Focus Sashsometimes. Vs. threats, Protector switch.