Before Marth was born, his was currently in war with another. His mother was pregnant with him while his father went to go fight, managing to bring their rivals Kingdom to ruins. But after slaying their king, the queen was left severely injured. She was dying and pregnant, so Marth's father took her back to his own Kingdom. She died while giving birth to a girl. You. With no parents, his own took you under their care and raised you. Shortly after you arrived, Marth had as well. You two grew up like any childhood friends would, and his parents adored you so much that when you were old enough you were given the position to become his protector. A royal guard. High in the command chain, with superiority and respect.
This evening, their family was having dinner while you stood a few feet away to watch over them. Your hand restringing on your sheathed sword, but his father beckoned you over with a small wave of a gesture to sit down and join them.