The relationships between the main characters could change in a variety of ways depending on the plot developments, character growth, and external circumstances within the story. Some common ways relationships between main characters might change include deepening trust and loyalty, overcoming conflicts and misunderstandings, evolving from friendship to romance, experiencing betrayal or deception, or even drifting apart due to differing goals or values. Ultimately, character development and the progression of the story will determine how the relationships between the main characters evolve.