Board Thread:Character Discussion/@comment-31770519-20161007073328/@comment-4975807-20161009050127

All deceased people within the OUAT universe go to the Underworld after death. If this is correct, then that means Daniel already went to the Underworld after the first time he died (when Cora crushed his heart). So does this mean he was there that whole time with unfinished business until he was revived by Dr. Whale? Now that I think about it, he and Mr. Gold/Rumple are the only two people who have died, gone to the Underworld and come back.

I remember zombie Daniel telling her that she had to let him go because living (in his revived state) was painful for him, and that she needed to learn to love again.