Note: This is a cancelled species.
First mentioned in a news post in January 2011, the Erif was a species planned by Dev (#10) for a short amount of time during the early days of felisfire, when it had only two breeds (Felidae and Xano). It was suggested that a new planet would be created outside of Felisfire with new lore, locations, breed etc. The Erif was to be the first breed of this new planet.
A couple more concept art sketches were posted and the Erif was alluded to a few more times while Dev (#10) was working on Felisfire. When they disappeared, the idea of the Erif and the new planet were discontinued (i.e. never brought up again).
Many users have noted, however, that the Erif concept art is similar to the Zerda, released 3 months later. The Zerda is generally considered to have evolved from the Erif concept (with larger wings, a fluffy tail and a sitting pose).
The Erif was shown to have extras equipable to the body, such as the flames seen on the right specimen and the drips on the bottom one. This was drawn in the time that custom mutations were in a feature in the works on FF, however, so it might have been meant as a similar extra.