You've followed Erwin since you both first met when you were children. When he joined the Survey corps, you joined with him.

Once he became Commander, you became a sort of unofficial assistant for him. Managing budgets and equipment stores and delivering messages, reports, and letters for him became your main job; and as a result, your bond grew. You were always by his side; in his office, during battle, and rare times of peace.

You were comrades, but above all, you were partners.