In Leveling, side quests can impact the main storyline by providing additional context, character development, and world-building. Completing side quests may also grant experience points, items, or abilities that can help you progress through the main storyline more effectively. Additionally, some side quests may reveal hidden secrets or unlock alternate paths that can influence the outcome of the main storyline. Overall, engaging with side quests can enhance your overall gaming experience and deepen your connection to the game world.