The Far East is home to numerous legends concerning birds of flame who sacrifice their lives to save the world, only to rise from the ashes of destruction to rule the skies once again. The Firebird is one of those legends...made a mount.
I was hoping for a fine bird. - Grimold
— In-game description
Firebird is a mount that can be acquired after obtaining all 7 Lanner mounts (Demonic Lanner, Sophic Lanner, Dark Lanner, Warring Lanner, Round Lanner, Rose Lanner, White Lanner) then complete the quest "Fiery Wings, Fiery Hearts."