Challenge different floors of the tower and defeat the enemies within to win Abyssal Stars. Monsters and humans alike flock to the tower in search of the secrets and treasures it contains. It is said that many secrets and treasures that have been long forgotten by this world lay buried within. It is now collectively called the 'Spiral Abyss'. Its structure is divided into the 'Abyss Corridor,' which connects worlds, and the 'Abyssal Moon Spire,' which leads to the unknown. To this day, the purpose of this underground city remains unknown. A massive underground city constructed by an ancient civilization long gone.