Element guide
Opposite elements are elements that can't be breeded directly. Below is a chart from Wikia.
how to breed opposite elements together
Sometimes, you might get a double dragon. Use these, or use standard 2-elemented dragons for a chance!
element list
The chart tells you which element is weak against which when defending. The first element of the dragon will tell you it’s weakness. For example, the Sea/Nature dragon Nenufar has Sea as it’s first element. Therefore, it will take double damage when hit by flame attacks and half damage from sea and nature attacks. It also takes no damage from terra attacks. These charts are from Wikia and dragoncityeggs.net.