Hellfire Wyverns were released on April 1, 2010, alongside Bright-Breasted Wyverns, Sunsong Amphipteres, Guardian of Nature and Nebula Dragons as a part of the "Mod Mayhem" release. They are unusual in that they have separate descriptions for male and female hatchlings, which only a few other dragons have. The females have a higher status ranking than the males do. Since the "7th Birthday" release, Hellhorse Dragons can be obtained by breeding a Horse Dragon with a Hellfire Wyvern.