I would reccemend at least level 25 for this but you could try it at a lower level first go
to the rip in the sky and find the loremaster click on the scroll furthest away from the skull
(at least i think you click on that scroll) and you should go to a war where you fight a fire 
army (not the dragon just the army)click on twilly and he will give you a weapon beat the 
entire army exit and then repeat thr process. 
P.S when you finish you get the dragon rider option in the part where you select what armour
you use in battles hope this cheat works.