Junsui is the second eldest child of the Tamashi family, and is the Second of the faction known as The Family. The Family is a faction, the first of its kind, to be made up of entirely siblings and it was founded by their father, and manager Tetsu Tamashi. 

Tetsu is known for his harsh methods and iron will, often resulting in what could be considered abuse on his children. But Junsui wholeheartedly stands by his father, seeing what he does as best for their family and creating their legacy. It is because of his elder brother Shinsuke’s reluctance to totally stand by Tetsu that Junsui despises him, seeing himself as a more deserving Ace of the faction.