I like the idea of Darcena being used as a mount when in her feral form
I couldn't make a saddle look correct, so she does not have one
Horn could be tugged to encourage fire-breathing
Collar is mostly to provide something for riders to hold on to, and will eventually have a more ornate design
Wing Claw could be used to encourage the position the wings are held in when walking and change direction when flying
Tail could be used to encourage a quick stop, or to present herself to a potential mate...