The lobo that stopped Emma from leaving Storybrooke has not been given an identity, but we have been given clues enough to determine it. In a sneak peek for tonight's episode,Graham is often featured with one lobo as his companion. In another sneek peak,the Evil queen later reveals that he was raised por wolves. Since everyone in the fairy tale land was affected por the curse,even animals, I believe that the lobo that kept Emma from leaving is the same lobo that was Graham's ally and that possibly raised him.