Board Thread:Dragon City Gameplay Questions & Answers/@comment-17718856-20130905105629/@comment-10090661-20130905163907

Legendary and Pure Dragons do not have any noticeable weakness. The Soccer Dragon is weak against Flame Attacks, and does normal damage against Metal Dragons. Try a lv 12 Metal Dragon against the Soccer, or if you have a lv 10 with Gold Stars, that will do as well.

For the Legendary and Pure Dragons, consider using Rare Hybrids -- they are designed for battle -- but avoid using Soccer or Gummy. His Soccer will come out and kick the life out of it. I suggest Armadillo Dragon or Cool Fire. Lv 15 should be fine.

Also if you get a chance, star up your Dragons in PVP for the bonuses before fighting that guy again.

Good luck!