Fake Vivi

Vivi is a combatant in the Struggle tournment played through as Roxas, although not considered "Vivi" by Seifer and his gang. You must combat Vivi once more as Roxas while searching for the truth behind the Seven Wonders of Twilight Town.

First Confrontation
Your first confrontation with Vivi is during the Struggle Tournament while playing as Roxas, this battle will be the most difficult of the entire Struggle tournament with Vivi being faster and more relentless than any of the other competitors. During the battle Vivi will close distance with you more often than the others leaving little room for you to run to, in addition you'll have to look out for powerful overhead swings where Vivi enlarges his bat. The last major attack to look out for is a rapid spinning Vortex-like attack where Vivi spins with his bat through to air towards you.

It's suggested that you just do whatever you'd normally do for the tournament, keep on the attack against Vivi and collect every single orb you can. Generally it will be a close call since Vivi will be after those orbs just as much as you are.

Second Confrontation
Your second time fighting Vivi will be when Roxas and the gang are searching for the "Seven Wonders of Twilight Town" on Roxas' second last day. When you go into the tunnel to find the "Moaning Ghost" Roxas will be confused to see Vivi...followed by multiple Vivis.

This battle is much, much easier than your first confrontation with each Vivi requiring one to two hits to dispatch. Just keep swinging your keyblade through all the Vivi clones until the cutscene arrives and you'll be through with it in minutes.