In the context of depicting the growth of Karasuno as a team, the author may have used the literary device of symbolism to represent the team's progression. For example, the team's uniform color or their mascot could symbolize their unity and development throughout the story. Additionally, the author may have employed foreshadowing to hint at the team's improvement or challenges they may face in the future, creating a sense of anticipation and growth. Furthermore, the use of imagery could vividly describe the team's training sessions, matches, and interactions, allowing readers to visualize and understand the team's evolution over time.