Board Thread:Dragon City Gameplay Questions & Answers/@comment-10873554-20130621151940/@comment-10090661-20130715005301

Cool Fire + Cool Fire should be fine. If a combination doesn't seem to work for you after say, 10 tries, I recommend you try another combo. The Random Number Generator (the engine that controls the chance for you to get something) for DC doesn't seem to be truly random. It may be easier for you to get the Legend Dragon you want with another combination / parents level.

You may end up with interesting dragons. :)