|Real Name||Nanao Watanabe|
|Aliases||Galaxy Seven, Seven-sempai|
|Voice (Japanese)||Daisuke Kishio|
|Voice (Tagalog)||Mark Muñoz|
|First Appearance||Ep 30|
|Key Cards||The GiantHero Titus|
|X-Rares||The GiantHero Titus|
The MobileFortress Castle-Golem
Seven's appearance is based on Galaxy's first design. He wears a light blue cape and a blue feather boa around his neck. As Nanao, he has short black hair, beady eyes, and wears a black boy's school uniform.
As Nanao, he is very quiet, normally speaking in monotone. He's easily frightened, and a crybaby. When he becomes Galaxy, his personality chages completely, giving him an ego and a fascination with his own beauty.
Seven is a third year student at Toaru Middle School, and president of the Battle Spirits club. He researches Nazo-Otona, and discovered a place which he named "Mysterious Space." Though the club was once huge, all the members were scared away by him, leaving him as the sole remaining member, and further damaging his confidence as president.
When Bashin began middle school, he, Striker, Meganeko and Smile all wanted to join the Battle Spirits club. Seven told them of his past adventures, though he believed they'd be driven away. He also mentioned that a Nazo-Otona was inside the school. Bashin investigated, and before him, Galaxy Seven appeared. Opening the gate to Isekai World, where the sky had now turned to night, he explained to Bashin that this was Mysterious Space. Seven easily won by means of a deck out. Bashin was impressed by his skill, and excited to join the club. When the others joined as well, Seven was overjoyed, and hoped they could gather enough members to make a tournament team.
After J joined Thousand Spirits Group, Bashin and his friends entered a tournament to try and get him back. Seven was one of the members of Team Shomen Toppa. However, he removed his name from the roster, causing the team to be disqualified. Bashin, unaware of this, found Seven in the bathroom. Seven explained that he had no confidence, but Bashin reminded him how amazing he was as Galaxy. Seven handed him a card, The GiantHero Titus, with no explanation. When Bashin returned, he found out what Seven had done. He and the others search for him, only to find Seven has become Number Seven of Numbers Elite. Upset by this betrayal, Bashin challenged him, this time giving Seven a deck out. Afterwards, Seven explained that he planned to teach Bashin that blue could be countered by blue. He gives Bashin Castle-Golem as well. As for his becoming Number Seven, he states it was planned in advance, and that this is his decision.
Before the King Uchuuchouten Cup, Seven is brainwashed by Number Nine, and returned to being Nanao under orders. Smile frees him, and he once again becomes Galaxy. He and Smile fight as a tag against Bashin and J, to determine which is the stronger combination. He and Smile are defeated, and recaptured by Number Nine. They're freed by J, Hayami and the pets, and return to watch Bashin's final battles.
In the epilogue, Seven is seen as Galaxy, watching a match between Smile and Masako. He comments that what Smile said was sexy.
Seven is stated to be a "hero of justice." He is a member of Numbers Elite, and disapproved of Smile joining.
He later appears to help Bashin and the others oppose Smile.
Seven's deck is blue, and is based around deck destruction.
His deck has contained at some point the following:
|The BattleBeast Bulltop||Blue||Spirit|
|The BattleBeast Rhino-Ceros||Blue||Spirit|
|The BearMan Beard||Blue||Spirit|
|The Berserker Troll||Blue||Spirit|
|The DragonSlayBlade Guy||Blue||Spirit|
|The GiantHero Titus||Blue||Spirit|
|The GiganticCat Blynx||Blue||Spirit|
|The Illusionist Mirage||Blue||Spirit|
|The MobileFortress Castle-Golem||Blue||Spirit|
|The Pikeman Jeffrey||Blue||Spirit|
|The Soldier Gustav||Blue||Spirit|
|The Absorption Triumphal Arch||Blue||Nexus|
|The Collapse of Battle Line||Blue||Nexus|
|The H.Q. filled with Fighting Spirits||Blue||Nexus|
|The Loss of Heroes||Blue||Nexus|
|The Rampart of Sapphire||Blue||Nexus|
|48-49||Tag with Smile||Bashin and J||Lose|