Hikaru Kain

Hikaru is a member one of the Dark Guilds, Grimoire Heart. He is one of the Seven Kin of Purgatory. He appears to be rather nervous, scared or simply has a speaking disorder. He stutters and then speaks what he wanted to say so fast that almost nobody could understand him. His catch phrase is "Woo-wee".

(Source: Fairy Tail wikia)