The Challenge Festival Event is a Challenge Event that features Heroes and enemies from all past Challenge Events. It is a limited-time event where all participating players compete for a high score.
The goal is to increase your Master Score by playing through stages and defeating enemies. The better your Master Score is, the better your placement will be in the leaderboards.
All players who have unlocked the Quests menu can participate in Challenge Events. There are three Difficulty Tiers (Rare, Epic and Legendary), all of which have multiple stages. Each Difficulty Tier of a Challenge Event has requirements that need to be fulfilled; for example, there will be limits on the rarity of Heroes and Troops allowed in battles. A player can complete any or all of the Difficulty Tiers.
Completing all stages of a given Difficulty Tier will award you a one-off completion reward. You can check the contents of the completion reward from the Challenge Event menu. In addition to this, at the end of a Challenge Event, participants will receive Participation Rewards for all Tiers they have competed in, based on their final rankings within each Tier. Participation Rewards can also be viewed by tapping on the Challenge Event Menu.
The Challenge Festival, no matter what difficulty you choose, is intended to be much more challenging than other parts of the game. Even the most powerful Heroes with the best tactics will face very tough battles. Some enemies in the event will have an Elemental Barrier that reflects all damage of their own element back at the attacker. In addition to this, each stage will have an Elemental Resistance, which decreases damage for each Hero of the same element present in the attacker's team.
Heroes from past Challenge Events (Pirates of Carelia, Guardians of Teltoc, Knights of Avalon, Fables of Grimforest, and Riddles of Wonderland) are granted Event Hero Bonuses within the Challenge Festival. Not only will these Heroes get increased attack, defense, and health during battles, but they will also be able to bypass Elemental Barriers.