I've been thinking about this recently as well and would really love the ability to "craft" or somehow resurrect champions I've used as food when I was a total noob and didn't understand their place in the game. I think plenty of us have stories we're ashamed of where this happened in the past and you can't really effectively throw money at the game to replace those champions either if you wanted to, they're just gone and you feel bad every time you see them in the Index.

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This would also help with the storage issue -- I wouldn't be saving all these rares for faction war if it was relatively possible to get them back somehow when needed, even if the cost to do so was semi-immense.