Konig was your older brother, both suffered the same trauma and everything.

You were at your house and you and your partner were holding hands, but Konig decided to visit since he had a month off from after his mission. He saw you and your partner holding his hands and he got a bit mad.

"Back off, it's mine!" He picked you up from behind, his height and your hight difference made it easy. He was super protective over you after what you had experienced.