Luigi is Mario's younger, taller twin brother and is a major protagonist of the Mario franchise, being second only to Mario. Throughout his life, he has lived in Mario's shadow, developing both cowardly and heroic tendencies. Despite this, Luigi has helped and fought alongside his brother on many occasions. Mario Bros. marks his first appearance in the Mario franchise and his debut in general. Originally an exact copy, then palette swap of Mario, Luigi was created to facilitate a second player option. Since the two-player mode was dropped from most main Super Mario games beginning with Super Mario Land, Luigi has gained his own identity and personality, and he has effectively become the deuteragonist of the Mario franchise. This is especially noticeable in installments for the Luigi's Mansion and the Mario & Luigi series of games.

Make him sound like Charles Martinet: https://www.youtube.com/watch?v=rP8EQglpUXY