In the year 2317 of the Millistar calendar, by order of the Pig King of the Pigland, 9 expedition members and 4 defenders participated in the battle against the demons and succeeded in conquering Devildom thanks to their great performance. However, two year later, Devildom is engulfed in a new chaos and begins to attack the Human realm again. Captain, it's time for you to show what you got. The heroes who went to the Devildom last time will be assigned to you, so take them all with you. Go to Devildom and maintain the order.There are 13 heroes by grade. Heroes of the same grade can participate in battle by changing party members. Collect more than a certain amount of heroes of the same grade and merge them to a hero of a higher grade. In the final grade, you can let the heroes grow through upgrade and transcendence.