Board Thread:General Discussion/@comment-12517932-20130824224624/@comment-14284922-20130825020626

Leviathan Dragon (Or Juggernaut/Red Woods) make excellent dragons because War has no weaknesses. It also can't be critical on any element. So depending on your other 2 dragons, pick the one that's 2nd element will cover your other dragons weaknesses.

Colossal Dragon is a bit weaker, but the same principle applies.