Board Thread:Questions and Answers/@comment-9240827-20130803014734/@comment-8122845-20130808013410

A fire dual boost would boost water and fire - I haven't seen any, but they might exist. The only dual boost that comes to mind is (Crab) Starland Praesepe and Karkinos. There's another water card, but I can't remember its name. You might be better off looking for cards with great drop to all ATK - they are equivalent to a great boost to single element, but they are not element specific and there are plenty of them.