Beating her in three turns without Namine is completely possible. Without Pooh or Piglett, it might be a little harder.
Namine is exceptional because she acts as a x2 Speed and a x3 Speed. That’s better than any buff card in the game. Pooh and Piglett (and Pooh&Piglett) are a x2 to Strength. The only other medal on par with these right now is KH2 Kairi, who gives x2 Speed. Without those three, it makes this fight very difficult.
Pairing any of the above (Pooh/Piglett/Pooh&Piglett/KH2 Kairi) with Diz/Vivi/Aerith/Nick&Judy/White Rabbit/Roxas&Axel&Xion can be just as good as good as Namine.
I’ve seen videos of people three turning her with Nick&Judy and Diz/Vivi/Aerith, but they have guilted Speed medals. Single targets like Tifa and Peter Pan (or if you managed to guilt Illustrated Yuffie last month) are amazing for this. Shadow if you have it guilted, or BC Mickey can be useful as well. You don’t have to worry about Special a lot, since you probably won’t run out in three turns as long as you save your second turn for auto-attacks.
The alternative is defense down medals, like Owl, Illustrated Ventus, Sora&Donald&Goofy, Megara, and Cinderella. But I can’t tell advise on their effectiveness, since I don’t have any of them. >_<
In short:
You probably need one of the following to properly 3 turn Master Ava:
~Namine
~Pooh
~Piglett
~Pooh&Piglett
~KH2 Kairi
~Illustrated Riku
~Illustrated Ventus
~Two or three high guilt Speed medals
Friend medals can help with the last one, but the buffs are up to you.
Never fear, though!! As the game continues, better medals will come out and keyblades will get stronger the more you upgrade them! Master Ava will always be in the game, so nothing is stopping you from trying again in a few weeks. ^_^ That Unchained title will be waiting for you!
<3 KCM
My Namine trick for beating Master Ava in Mission 425 in three turns!
Here’s my build:
Lady Luck +23
Namine
Buff Medal (Aerith in this case)
Buff Medal (Piglet or Pooh is best!)
High Damage (Tifa 50% guilt +1000)
High Damage (Sephiroth +1000)
Friend: High Damage (Marluxia +1000)
—Attack boosts on damage
—Defense boosts on buffs
On Turn 1, she starts with x2 attribute strength.
On Turn 2, she starts with x3 attribute defense.
On Turn 3, she starts with x3 attribute strength.
Hitting Ava gives way more Special than it should, so abuse that.
Use Namine on all three turns.
Use all buffs/damage on turns 1 and 3.
Make sure your buff cards are strength only, because Namine will steal her type-strength.
If you’re not taking her out, you need stronger damage or better procs!
Gives the title: Unchained
In KHUX Theater Mode: Episode 16, the search for Ephemer takes a detour through Agrabah, only to be cut short by Master Ava.

