In the Mass Effect trilogy, who is the main protagonist?

Shepard is the main protagonist in the Mass Effect trilogy because the entire series revolves around their journey and decision-making. As the player assumes the role of Shepard, they guide the character through their quest to combat the looming threat of the Reapers, unite various species, and make critical choices that impact the galaxy's fate. Shepard's actions, relationships, and personal development are central to the storyline, making them the driving force behind the narrative and the ultimate hero of the trilogy.