Legendary Planet Legendary Planet , known in Japan as the Planet Series ( シリーズ " Puranetto Shirīzu " ) , is a series of monsters with various Attribute s ( primarily DARK ) and Type s ( primarily Fiend and Warrior ) who serve as a major plot point in the " Yu - Gi - Oh ! GX " manga . All members of this series are Level 8 Effect Monster s , except for the following : This series was created by the father of Aster Phoenix while he was possessed by Tragoedia . It consists of ten powerful cards , each analogous to one of the major bodies in the Solar System at the time of the manga ' s first release : the Sun and the nine planets , including Pluto . The cards are named accordingly , with all of them possessing some sort of reference to their respective body within their names and artworks . Though not initially revealed , all the cards in this group have an ability that saps small amounts of energy from duelists who wield them . This energy was used by Tragoedia to unleash his heart from " Winged Kuriboh " . History . The existence of the Legendary Planets was first shown when David Rabb Summoned " The Big Saturn " against Syrus Truesdale , during which it was stated to be a member of the series , like Jaden Yuki ' s trump card " Elemental Hero Terra Firma " . Reggie MacKenzie was then shown to possess another of the Planet cards , " The Splendid Venus " , which she used against Alexis Rhodes . Jaden and David would use their cards during the tournament , alerting David and Reggie to the fact that Jaden had Koyo Hibiki ' s former card , and David would be rendered comatose during the tournament , his Planet likely being obtained by Principle Mackenzie when he arrived at Duel Academy . Reggie is later defeated by Jaden , losing her memories of many of the events , but retaining " Venus " . It was also revealed during her musings that the Planet cards were connected to Aster Phoenix ' s father . The fourth monster of the series , " The Tyrant Neptune " was used by Jim Crocodile Cook in his Duel against Atticus Rhodes , though unlike his sister , Atticus won his match against a Legendary Planet . After Aster Phoenix defeats Atticus , Principle Mackenzie gave Aster what he referred to as the " last " of the Legendary Planets ( likely due to having distributed the remaining cards at that point ) . It was at this point that it was revealed that the Planets had been created by Aster ' s father while possessed by Tragoedia ( though the latter detail was withheld from Aster ) . In the one - on - one matches between the Japanese and American Academies , the sixth monster , " The Despair Uranus " is used by Adrian Gecko against Jaden , however , Jaden managed to defeat " The Despair Uranus " and Adrian , and Tragoedia reclaimed " Uranus " . Chancellor Sheppard ' s musings revealed that to the public , the Planets had been mainly unknown , having apparently vanished after the death of Aster ' s father , and he theorized that the remaining Planets were also in the hands of the American students , seeing as three ( Saturn , Venus , and Uranus ) had already been . He was proven correct , as " The Tripper Mercury " , the seventh Planet monster is used by Jesse Anderson to defeat Syrus Truesdale . Chazz Princeton managed to defeat Axel Brodie and the eighth planet card , " The Blazing Mars " . Aster would use his Planet , revealed to be " The Grand Jupiter " to defeat Alexis , and Jim would use " Neptune " to defeat Bastion Misawa . " The Suppression Pluto " was used by Atticus to defeat Jaden , allowing Tragoedia to reclaim both " Winged Kuriboh " and " Terra Firma " . Mackenzie recalled his puppets and reclaimed the Planet cards from them , as well as obtaining " Venus " from Reggie after she spied on him . Mackenzie ' s Duel against Aster would reveal that Principal MacKenzie himself holds " The Supremacy Sun " , a card based on the star at the center of the solar system , which keeps all the planets in place rather than a planet itself . After defeating Aster , this put all ten Planets in Mackenzie ' s possession . Using the energy gathered by the Planets and " Winged Kuriboh " , Tragoedia extracted his heart from " Winged Kuriboh " , giving him the capability to return to his true form . When challenged to a Duel by Jaden and Chazz , he returned both " Winged Kuriboh " and " Terra Firma " to Jaden , and used " The Sun " against them . After his defeat , the whereabouts of the Planets were not disclosed , though it is shown that " Terra Firma " was returned to Koyo Hibiki . Names . In the " OCG " and Japanese manga , the Planet Series naming convention is " The ( adjective ) PLANET " ( with the exception of " Terra Firma " , whose " OCG " name is " Elemental Hero The Earth " ) , using English words written in all capitals . In the English manga , the word " The " is removed , whereas in the " TCG " , with the exception of " Venus " ( which is just called " Splendid Venus " ) , the names are kept the same as the " OCG " name , minus the capitalization . " Terra Firma " was used in place of " The Earth " . Trivia . In the " GX " manga , Alexis Rhodes has faced many of the revealed Planet cards , and she has lost each match when she faced one . In her match with Jaden Yuki , she fought " Terra Firma " . Against David Rabb , she lost to the " The Big Saturn " . In her Duel against Reggie MacKenzie , the latter used " The Splendid Venus " . She later faced Aster Phoenix in the American vs Japanese one - on - one matches , and lost to his newly obtained Planet " The Grand Jupiter " .