Board Thread:Questions and Answers/@comment-26430525-20170730162610/@comment-27718903-20170730190823

Glasswing is the most difficult opponent in the arena (as well as the most powerful ally one can have), because unlike other champions, Glasswing is both Ultra Rare and has a resistance to Metal. Literally Diamond types are the only dragons that have anything other than 10%, and it's not very high. So if you have one, feed it. They are remarkably cheap. If you don't have one, then getting it should be prioritized.

The Fire strategy is the most viable way of dealing with these guys, so I highly recommend it.