Anyone you ask will tell you that Spy x Family is a comedy first and foremost. Its setup is completely absurd in ways that just beg to be utilized for jokes, and it loves to put its characters in situations where they're completely out of their depth, to hilarious results. But if you dig just a little deeper, you'll find what I believe is the beating heart of the show—it is the gnawing seed of fear planted in the mind of every viewer the moment they start to become attached to the anime's main trio.
"What's going to happen to this family?"
The starring members of the anime who form the eponymous family are almost instantly lovable, good-hearted people. But they are each participating in this grand deception for their own reasons, fooling each other and the world because it benefits them in some way. Loid is a spy working on the most important mission of his life, and he needs his fake wife and fake daughter to play along so that he can do his part to prevent a war from breaking out. Yor is an assassin who fears the current social climate will get her arrested just for being single, and agrees to be Loid's pretend-spouse simply so she can deflect suspicion. Anya, the very young daughter, has the ability to read minds, and helps assemble this family spur of the moment, mostly because she thinks it's super cool to have a spy and an assassin for parents.
From the very beginning, everyone involved is clearly shown to be self-interested. However, as the story progresses, it becomes obvious that emotion will begin to overrule logic. As Loid falls into the role of parent for the sake of his mission, and Yor for the sake of her standing, they both find themselves actually caring about their fake daughter. Anya, meanwhile, desperately clings to her new family, hoping against hope that she will not be tossed aside the way she has been many times in the past. The more time these characters spend together for their own reasons, the more their fake bonds become legitimate, calling attention to the double meaning of the Forger surname. "To forge," can mean to make an illegitimate copy of something, but it can also refer to the act of creating something very real.
Is the Forger family fake, or real? Will Loid leave them behind when his mission is complete? Will Yor return to her old life, where killing is the only thing she can do? Will Anya be returned to an orphanage, having been abandoned by yet another family? For as much laughter as the show generates, there's a hope and a fear behind it. That, I think, is how this anime has cast such a spell on people, and I admit I'm right there with them, completely entranced.
