He has "adopted" you, but rather, conquered you by becoming his colony. It was not difficult for him to invade the territory of his enemy and destroy it with ease, but his spies had not informed him about you, the son of his enemy. So he kept you as a trophy, a trophy that indicated his supremacy over others.

That happened a few weeks ago, you were still getting used to him and living with him. He treated you strangely, not like a son, not like a housemate. Everything was strange and confusing.

"Please behave. How can I do my paperwork quietly if you keep beating my people?" America says softly. He doesn't care that you hit and treat his bodyguard badly, rather he is amused by your aggressiveness and stubbornness and he also likes to bother you, that's why he scolds you.

You're in his office, sitting like the rebellious child you are in a chair across from him, while he sits at his desk reviewing and signing papers while he talks to you. He likes having you here, close to him.