Duel Monster Spirits Duel Monster Spirits , Duel Spirits , or what are now known as Duel Monsters is the name given to the magical , spiritual , and otherworldly creatures who have the capability to be summoned by a duelist . Ancient legends and carvings of Duel Monsters inspired Maximillion Pegasus to create the popular card game of the same name . They live primarily in the Duel Monsters Spirit World , although their relationships with humans and Earth are sometimes unclear , and differ within the different Yu - Gi - Oh ! series . It is unknown if every Duel Monsters card created within the Yu - Gi - Oh ! universe has a Duel Spirit counterpart that can be summoned accordingly . In some cases , these spirits seem to form a strong bond with a specific human . In Ancient Egypt , these spirits took the form of a person ' s Ba ( in Egyptian mythology , the Ba was the other half of your soul - your personality ) . In Egypt , some people could possess multiple spirits as their Ba . A person ' s Ba can fuse with their Ka ( life energy ) to fuse the person with their spirit , such as when Mahad became Dark Magician . It is unclear how this relationship takes form in the modern age , and in each other Yu - Gi - Oh ! series - for example , the Ba of each Signer could be their Signer Dragon , but it is never stated . When a person dies , they can either pass on into the afterlife , or fuse with your Ba to become a Duel Monster Spirit ( like Mahad and Mana ) . It is highly implied that the afterlife and the Duel Monsters Spirit World are both connected somehow . These spirits have their own societies in each part of the spirit world ( the spirit world is explained by Yubel to be several entirely different dimensions ) , and there have even been conflicts between the spirits of some dimensions , such as between DARK Fiend - Type monsters against LIGHT Fairy - Type monsters or Warrior - Type monsters against Dragon - Type monsters , among others . Duel Spirits were allies of the human world in many ancient societies such as Atlantis , Egypt and the People of the Stars . The Earth has been both aided and plagued by both good and evil spirits . One section of the spirit world appears to be based of mostly Fairy and Dragon type monsters although Dark Magician Girl appeared to be the leader of them . Her presence in this place may indicate other Spellcaster type monsters such as Dark Magician also live there . The most notable Duel Spirits from this area are the Legendary Knights of Atlantis , Timaeus , Critias , and Hermos who are its guardians . According to Dark Magician Girl , the spirit world has existed as long as mankind has existed . Another section is Neo Space , which is the realm beyond Earth in outer space in which consists of many Alien duel spirits such as Elemental Hero Neos and the Neo - Spacian s . They believe in a being with the power to bridge the worlds of the Duel Spirits and the humans called the Supreme King , who ' s destined to save both worlds from The Light of Destruction . Another unique section of Duel spirits are the Number s , whose powers originate from both Astral and Barian World s . Even several spirits were chosen to act as guardian s to protect their respected Number cards on Earth . History . Duel Spirits have played a pivotal role in human history dating back at least ten thousand years . Humans somehow found a way to summon them here the human world using magic and spells . The Ancient Egyptians sealed their spirits ( or the means to summon them ) in stone tablets by ripping a person ' s Ba from them , killing them in the process . These tablets resembled duel monster cards and later inspired Maximillion Pegasus to create the game . In doing so , Pegasus sealed the duel spirits ( or means to summon them ) in the cards , similar to how they were sealed in the tablets . However , they are only truly summoned when magic forces are involved or when they are involved with certain individuals . Otherwise , they are merely represented by holograms projected by KaibaCorp technology . Therefore , while they have a true physical form in their own world , they cannot take physical form on Earth without being summoned here . Duel Monsters Spirit Day is an exception however , being the only day of the year when Duel Spirits can take physical form on Earth without elements of magic being involved . Back in the times of Atlantis , the spirits came to the aid of Ironheart , Chris and the survivors of Atlantis after its king , Dartz , corrupted and brainwashed by the Orichalcos , began a conquest to destroy all life on Earth to recreate it . They sent a huge army against Dartz ' s Orichalcos soldiers and the Great Leviathan in the Battle of Atlantis . Neither side was victorious , Atlantis sank into the ocean depths and the Duel Spirits were sealed away until they be needed again . Around that time , the Crimson Dragon and its servants the Signer Dragons battled the evil entity called Red Nova to exhaustion . It was only through the help of a Legendary Signer that Red Nova would be defeated and sealed away into the Earth and become the first of the Nazca lines , thus becoming the first Earthbound Immortal . Abilities . Regardless of their nature , Duel Monster Spirits seem to possess different powers depending on who the monster is . For example , Jinzo and Yubel have the ability to possess people and take on a physical form if they have enough energy . Winged Kuriboh could take Jaden Yuki to another dimension . Brron was capable of performing a ritual using negative feelings to create " Super Polymerization " , to name a few . A common trend however is that seemingly all Duel Spirits can Duel themselves and have their own Deck , which in most of not all cases will have at least one copy of the card they themselves represent , regardless of rarity . For example , in " Yu - Gi - Oh ! GX " the spirit of Dark Magician Girl had her own card of " Dark Magician Girl " even though Bastion Misawa claimed Yugi Muto was the only known owner of the card . In some cases during Duels , the Duel Spirit can Summon themselves to the field , as seen with Gravekeeper ' s Chief and Don Zaloog , or a doppelgänger of themselves will appear , as seen with Kaibaman and Yubel .