(Typically for the Event Dungeons, they are much harder compared to the difficulty required to unlock them.)
*For the majority of Event Dungeons, when you clear a Dungeon, you'll earn Points. These can be typically used to get special Event Cards and roll for Fodder Material.
*Many Event Dungeons also have Special Cards that may drop at the end of the Dungeon (typically Sub Cards).
*Not every Event Dungeon is the same; some are much easier to deal with than others (often due to Boss Mechanics).
*Like Normal Dungeons, Event Dungeons also have Treasure Rewards. However, they are not guaranteed to drop. (TDK Treasure is a near-guaranteed drop however.)
**However, if you have truly bad luck, the Treasure is guaranteed to drop after clearing a Difficulty 10 times.
*The first three difficulties are relatively Easy to beat. You shouldn't have much trouble beating them.
*From Demon difficulty, it gets a bit harder as the enemies start to gain more Attack and HP. You'll need to start having a well-rounded Deck.
*There's a significant gap between Dragon and God difficulty. The Bosses are significantly harder from God difficulty onwards, and you'll need a fully-powered up Deck to stand up to them!*True Dragon King & Super Dragon Emperor are currently the hardest Difficulties. They typically offer beefed-up Bosses often with altered mechanics. Sometimes, you'll have to face several Bosses in a row (or together)!