God dammit, here we go again with the false betrayal plan. Hope this one falls apart like the rest.

@Vortaxonus  
Still they’d have to transport the werewolf to the general area for best effect. and assuming it doesn’t take instant effect that would mean losses for the Crusaders.

@Wing8492  
Assuming you can’t spike it in a drink or something.

those moron belive do for the sake of equestria but no! all then are become traitor! if all theme succeed to kill all what them call monster darkness, all then will excuted for murder and traition! those crusader are total fool to not see what celestia a try to tell them! all then are blind by vengence and not see the good side of all this! yes some vampire are jeck and mose be kill but not all them! the same for werewolf! the stupid brother of derpy is so stupid were he kill the love of his sister! he belive derpy be control by a spell! only the unicorn and alicorn can use spell! plus the werewolf pony of the village work so hard to be see as good pony! all them want live on equestria ones again! but no! those jeck come and kill them all! those village be hide for good reason! for those moron! but all this is fault of a traitor who tell were those village is! but some info of those village be take by force on the guard so are on duty to protect it! were those village be attack the dawn guard and werewolf a try to protect the village but some traitor be in their rank of dawn guard! traition is what make thing more hard for those want to protect those can’t protect them self and those want live in peace! those moron are worst the evil vampire! why? no mader the evil thing those vanpire do is will nothing to those kill other for their stupid jugement! plus in the rank of dawn crusaders many of kill for pure fun! those are worst of all! i like their armor but not their action!

 
what happens when you use it on normal ponies?

@Dirty Bit  
Should not be a dick… what if I said “become monsters themselves” it would be an insult to to those poor creatures.

Again, giant flaw in this plan they need to get close to the party to safely inject the werewolves with the night fury. Which means it’s easier for them to get caught. Since doing it before and away from the party risks them getting killed by the captured werewolves.

@Dark Tail
 
He who fights monsters…

When you set out to kill monsters only to become the very thing you swore you would destroy.

Yikes.