Work your way up to B class. There is a battle called the Trial Cup in the 4th week of April. There is a dragon at this match. Defeat that dragon and get up to A class as fast as you can. When you get there you should sometime get invited to the August invitational. It is the 4th week of August. Defeat the black dragon in that and recieve the DRAGON TUSK as your prize. Breed the DRAGON TUSK with the DINO-NAGA and NAGA-DINO to get the Dragon Monster.