By breeding two pure Rainbow type dragons together (Rainbow only). As a random single type result of breeding two pure Diamond type dragons together (Diamond and Infinity). This pairing may result in any currently available pure dragon of the Red, Green, Yellow, Blue, Purple, White, Pink, Black, Mythic, Cosmic, Fairytale, Stone, Dino, Rainbow, Gemstone, Zodiac, Tropic, Royal, Metal, Olympus or Diamond type. read more
Unlike other dragons that are available through breeding, the Double Rainbow Dragon's breeding and incubation time is 19 hours, while cost to speed up is 18 gold. It is unknown at this time whether this is intended behavior or a mistake. read more