Shin Nagumo was an orphan.
Though that wasn't something he particularly liked to talk about, which was why he hardly ever mentioned it.
Even if he wanted to, it's not like he had anyone around him who he was comfortable sharing the information with.
The Director position of the Shining Order of Sacred Mercy is past down from generation to generation from all members of the Nagumo clan.
However, none of them are blood related.
The director spends their entire life abstaining from the pleasures of romantic or sexual relationships; with their only commitment being to the order.
Because of this, they adopt children from alternate realities and raise them as their own while teaching them all about what it means to serve their organization and fight against the abyss.
But that does not mean that they don't grow attached.
Shin Nagumo's father was the best man he'd ever known.