To explain, when attacking with Fire, Firebird deals double damage against Water and Ice, half damage against Earth and Fire, and no damage against Metal. When attacking with Plant, Firebird deals double damage against Electric and Dark, half damage against Water and Plant, and no damage against Fire. When defending, Firebird takes double damage from Water and Electric, half damage from Fire and Metal and take no damage from Plant.
The egg of the firebird is the pendant in Deus' staff.
The Firebird Dragon barely possesses any draconic traits and resembles more as a Phoenix.