Board Thread:Dragon City Gameplay Questions & Answers/@comment-99.25.32.14-20130626005315/@comment-9946604-20130627204451

Realistically, it SHOULD be dark, but it isn't.

Each element has one that it's immune to, and only one immune to it. No element is immune to dark, and ice is immune to nothing.

I don't know if this was intentional or not, but it totally seems like a mistake.