Yuki Gekko was the Eldest Child of the Gekko Family.
- Main article: Shinto Christian Mythology
This 12th-grader, president of both Seiho Academy's student government and its modeling club, is adored by the student population Talented at Gunpla building and battle, he made it all the way to the world championships of the last Gunpla Battle tournament. He's also known as "The Crimson Comet". Yuki is seen monitoring the school grounds with Monta, where he sees that Sei is busy designing the Build Strike Gundam's new equipment. Later when China visits the stadium for the Gunpla Battle Championship out of curiosity, it is shown that Tatsuya and his Zaku Amazing are battling against an opponent's ZGMF-1000/A1 Gunner ZAKU Warrior. Tatsuya comments that it's a well made Gunner Zaku Warrior and that he doesn't really want to damage it, where he then shoots down the scope of its M1500 "Orthros" beam cannon, then puts his Zaku Amazing's Heat Nata against the Gunner Zaku Warrior's neck, making the opponent surrender. Tatsuya becomes frustrated and unsatisfied, asking himself if he is being arrogant to wish for a true battle. He then sees China in the audience and greets her, asking her if she was interested in Gunpla Battles. She tells him it isn't like that, where Tatsuya asks her if she came to cheer for Sei instead, as his match is coming up. After China sees Mecha Paul Gekko getting crashed into the RX-79BD-3 Blue Destiny Unit 3 and into the White Angel's Hanger that is about to save Kaede's Gunpla, RX-78-10 Wing Gundam Bijuu. Ple Twelve in her Unicron Banshee in which she confused him for a Gundam and tore the Blue Destiny Unit 3 apart.
Later on, Yuki joined forces with Paul Gekko and the other Members of his Family on defeating the Juubi's Jinjuriki, Cloud thus stopping the Eye of the Moon Plan which was completed at the Ka Boa Bu (which is the Fortress where the Hylian Federation and the Kuro Akatsuki fought in the Place).
- Yuki Gekko is similar to Yuki Tatsuya.