How do you defeat Lupin when he is a werewolf and you have Buckbeak with..

Go to Fred and georges shop and get all GRAND wiggenweld potions and sp cards. Fight lupin and use grand wiggenweld potions on buckbeack nonstop. Let buckbeak kill lupin. If his life is low, use harrys speciaol moves to replenish him.

Here's a few things I always do:

1. Have Hermione use Fumos on Buckbeak - using this spell means that Buckbeak is hidden from view, therefore Lupin misses more often.

2. Use Harry's special moves - Cracker Jinx, Bludgers, Sonorus Charm (think the other is called something like Horklump Spore): using these mean that Lupin suffers 15-45 damage each time. It's better to use these as spells (exc the ones I've mentioned) only cause 1 or occasionally 2 damage to him.

3. Use Petrificus Totalus once (probably best to use it when Buckbeak's health is low) - you can only use it once as after that Lupin becomes immune to it

4. Use Wiggenweld Potions on Buckbeak as and when needed