Heaven Drake
The strongest Dragon-type monster, which only appear in the trio of final dungeons, and thus, they are as dangerous as any other monster that appears on these areas. Aside of their high stats, they can use the Poison Mist attack, and also have access to two new skills: Aurora Breath hits all party members once and causes Sick; while Calamity hits all party members once for large amounts of damage. Aurora Breath is relatively easy to block, but Calamity isn't due to being one of the attacks that causes the game to lag during the Defense Phase, so the player should be very careful against these monsters, heal the ailments they cause with their attacks, and try to use Song Magic to defeat these monsters quickly.
Trivia
Apparently, these monsters were going to be called Fire Drakes early in development, as a text dump of the game gives the "Fire Drake" name alongside a description, while the "Heaven Drake" entry appears without one.