If you are having difficulty clearing the final stages: Beginner’s Strategy Guide to Challenge events
If you are looking for Strategies to Maximize your scores
Majority of Monsters: Ice & Nature
Therefore you will want to bring Nature and/or Dark heroes.
*Multiples of a single hero can be used.
**Heroes are planned for mono color usage – to maximize the chance to be able to clear the first wave of enemies with a good cascade of tiles. Alternative hero choices here