[quote=@Masaki Haruna]
Black Mamba action!
Everyone will be curious, boy or girl? What did Mamba show to Kyuuten that made him convinced??!?!?!!? All these questions!
Tune in to Fairy Tail Z!

Who is the hooded man? 

@Rai, I got no clue with the vials. It's Gwen time!
[/quote]

They're for contaoning the fragments, which are active and will seek out a new host upon the death or defeat of their current one. It cannot be resisted, will give character power boost, but will turn them insane wity bloodlust. You still control character, they just become crazy and want to kill everything.