Gekko Tenma Gekko Tenma 「 天馬月行 , Tenma Gekkō 」 is Yako Tenma ' s older brother , although only slightly older , since they are identical twins . Gekko ' s name most likely derives from " gekko " meaning moon ( something that Yako later alludes to ) , and " Tenma " which came from Pegasus ' Japanese alias in " Reshef of Destruction " , Taiyo Tenma , as he and Yako were initially adopted by Pegasus . He is commonly called and described as being a " perfect Duelist " . However , Gekko later comes to believe that he is a " perfected Duelist " , as everyone else he Dueled improved while he didn ' t . Appearance and Personality . Gekko is identical in appearance to his twin brother Yako , with long silver - green hair . However , his attire is similar , but noticeably different , wearing a heavy maroon coat over what appears to be a white version of Yako ' s clothes , though he does not wear gloves . In the past , both he and Yako wore dark suits . Gekko is a far more calm and composed individual than Yako , and usually does not raise his voice . He was much more upbeat and cheerful in his youth ( with Yako being the more quiet and shy individual at that time ) , but is more subdued following the death of Pegasus . Following the loss of his adopted father , he became opposed to seeing others suffer the way they did , which was part of the reason that he assisted Yugi Mutou . He is also fiercely dedicated to his brother , and opposed him in an effort to save him , and regretted that he was forced to help him deeply , as well as Yako ' s actions and that he had been unable to stop them himself . Biography . During the early years before the time of the Duelist Kingdom tournament took place , Yako and Gekko were adopted by Maximillion J . Pegasus and raised and trained to be Duelists . It is unknown what happened to their parents . Throughout the years , Yako began to develop a strong hatred for Gekko because he was constantly denounced in Gekko ' s presence such as being called " a bad copy " . After one Duel , Yako ' s strategy fails to Gekko ' s Deck . Gekko says that it was a good strategy but probably would have worked with better cards that he begins to write down on a list . However , Yako stands and runs away in shame . Later on , Gekko ' s body was hacked by his brother , Yako Tenma , before the R . A . Project began . During Gekko ' s debut , Yako was controlling his body to make it seem as if it was Yako himself . He forces Yugi Mutou to a Duel and ( against his own judgment ) Summoned " The Wicked Dreadroot " which allowed Yako to advance the RA Project to the next stage . After having been rescued by Croquet from Yugi ' s final attack with " Arcana Knight Joker " and , there - by , losing the Duel , he decides to help Yugi defeat Yako and stop the R . A . Project . He states that even though he too would like to see Master Pegasus ' face again , he does not want to have to sacrifice people like Yako . Gekko ' s first Duel with Yugi is against Ted Banias , and he is told by Keith that if he loses , Yugi will be barred from ascending furthur . Although at first it seems as if Gekko is helpless , he turns the Duel around and ultimately annihilates Banias after encouragement from Yugi . His second Duel was much later against Richie Merced , another Duelist who was taken in by Pegasus . Throughout most of this Duel , it seems as if Gekko is winning his way slowly , however , Richie manages to turn the tides on him and claim victory . Richie later claims that Gekko ' s haste to save Yako was what cost him the game . This meant that Yugi would not be allowed any further up the KaibaCorp Skyscraper . But Yugi and Gekko are relieved of this when Mokuba Kaiba opens the locked door for them from the control room , though Gekko is initially unwilling to continue on . When Yugi and Gekko make it to the next room , Jonouchi and Honda come out of an air vent in the same room . As soon as Jonouchi comes out , he tells Yugi to stand back and punches Gekko , whom he mistakes for Yako , extremely hard throwing him against the wall . After figuring out that he is indeed Yako ' s twin , Jonouchi apologizes , but Gekko denies it saying that he deserved it . When Keith Howard arrives to Duel Jonouchi , Gekko warns him about the significance of the Black Disk , realizing that Keith had to have defeated Richie in order to obtain it . During the final Duel between Yugi and Yako , Gekko helps to release Yako from the spell set on him by " The Wicked Avatar " . He had given Yugi the " Divine Evolution " card , which he had used when controlled by Yako . Gekko tells Yako that even though he may have been called " perfect , " that means that he cannot progress or become stronger unlike Yako . This allows Yako to realize that he can actually surpass his brother which gives him a new purpose and a strive to finish the Duel with Yugi . After the Duel , Yako thanks Gekko for not letting him give up before tearing " The Wicked Avatar " card to pieces . Decks . In a flashback , he defeats Yako using " Rogue Doll " . Possessed . In order to test the powers of " The Wicked Dreadroot " , Yako possesses Gekko and forces him to Duel Yugi . The Deck focused on swarm ing the field with " Seraphim " monsters in order to bring out " Dreadroot " , while countering the opponent with cards such as " The Selection " . Elf . Gekko plays an " Elf " Deck , which focuses on swarming and using the effect s of the " Elves " to support one another . He makes heavy use of Equip Spell and Trap Card s , even using " Armament Reincarnation " to use them as monsters .