The term 'Friend of D'Artagnan' refers to the three musketeers, Aramis (6 letters) and Athos (5 letters), who were close friends of the protagonist in the novel The Three Musketeers by Alexandre Dumas. Aramis was a young man of noble birth who was a member of the French clergy and had a strong sense of honor. Athos was a nobleman who was a skilled swordsman and a loyal friend. Together, they formed a formidable trio of musketeers who fought for justice and defended the honor of their beloved D'Artagnan.