The Rise of Tiamatis a direct sequel to Hoard of the Dragon Queen, and it continues the story of a villainous dragon cult’s attempts to resurrect Tiamat. The book as-is is difficult for a DM to navigate and run a game with, but a veteran can tweak and homebrew this campaign into an...
Even with the "kit" classes in the Complete Handbook series, your characters are going to be pretty wimpy. Even at 6th level, none of those character classes could hope to kill even a monster as insignificant as Tiamat without a large arsenal of magic items! (Of course, by 6th level, ...