Maybe red is strong against Ice Age type dragons? Kooky beat one with Forestfire, I've done it with a Landworm and Aceblade used an Athletic. I know it's a too small sample to draw conclusions from but it would make sense since fire melts ice.
Managed to beat the arctic isle dragons with either crusader and helios.
And defeated Icecrown with Crusader using 2 bashes.
Red does seem to work on the Blizzard types from what others are reporting. I was able to beat the Blizzard with my Epic Landworm but red does not seem to work on Abominable, I have tried Epic Aether as well as Epic Parakeet, those have failed, really hate to use ultimate, would love to figure out these colors, trying black or pink next.
I decided to try red again and my Epic Honey Bee took out Abonimable BM. Maybe just a run of bad luck with the reds before. Someday I will figure this all out .
I'm stuck with flower
Any help! I defeated it before but now I can't