Board Thread:Spoilers!/@comment-4453062-20151110051825/@comment-24674051-20151204224217

Regarding the appearance of Dark ONe Robes, I think Rumple was originally in robes similar to these robes when he first became the Dark One. (Right after Killing Zoso, who was also wearing the robes).

Revived Rumple probably does not have to follow rules. and Head Rumple is going to appear in a way that is at least somewhat familiar to the new Dark One. He's not really there, and his appearance does match what he looked like for most of his reign.

As for Dark Swan, her powerful light magic may have factored into her appearance. She appeared in robes, just not dark ones.