Board Thread:Spoilers!/@comment-5899967-20160321134614/@comment-24674051-20160322165129

Only thing is, Hades is not going to willingly give up a soul, not even Killian or Liam. Hades wants to increase his power base, which means he wants more souls. That's one reason he wanted control of Rumple, since Rumple was one of his biggest suppliers.

In fact, in the conversation between Hades and Rumple, Hades flat out said that he wanted Rumple as a supplier, that Regina was not the best, and has gotten soft. Which, on a side note, tells us that they just canonically told us that Rumple has killed more people than Regina.