The protagonist enters the realm dungeon as a walker to complete the task and obtain source energy, equipment, skills and permissions. If he fails, he will be left in despair without any chance of resurrection.
Realm dungeons cover all themes: martial arts, fairy tales, science fiction apocalypse, Cthulhu strange stories, magical epics, urban anecdotes, mythical primitive worlds, etc. The difficulty level is normal → difficult → nightmare → hell → end. The higher the difficulty, the more generous the rewards will be, and the mortality rate will increase exponentially.
