Unfortunately Achilles is an ultra rare and very hard to get. It's an Olympus/Diamond hybrid and one of the best fighters in the game. It has a 47 hr. breeding time. I don't have that dragon yet after playing for 3 years. Maybe I'll get lucky and get one soon.
For a dragon to use against Quasar, maybe try a high level white/blue/red hybrid or white/purple hybrid. If you do have Angel (Diamond/White) then use him first.