A young beagle from rural Gascony, D'Artagnan (known as Dogtanian) carries a wound-healing ointment from his parents. Determined to join the Musketeers of the Guard in Paris, inspired by his father's past link to their commander Monsieur de Tréville, he journeys to the capital. His fierce confrontation with the Comte de Rochefort leaves him penniless with a broken sword. Upon arrival, his attempt to duel the Musketeers Athos, Porthos, and Aramis is interrupted by Cardinal Richelieu's guards; he allies with the trio, defeating them and earning their respect through his swordsmanship. Though initially placed in a lesser guard unit, his bravery captures King Louis XIII's notice.

Dogtanian forms a romantic bond with Juliette, a lady-in-waiting to Queen Anne who is frequently targeted by Richelieu's schemes. His loyalty to Juliette and the queen drives his actions, including recovering stolen diamond studs to thwart a plot against the queen. He adopts the Musketeers' motto, "One for all, and all for one," cementing his bond. Accompanied by the mouse Pip (Pom in original versions), who offers advice and comic relief, Dogtanian matures through duels, rescues, and missions across Europe. His exceptional swordsmanship allows him to defeat formidable foes like Rochefort, Widimer, and the Blue Falcon.

In the sequel *The Return of Dogtanian*, he is an established Musketeer facing new threats, including the villain Blanc Bec. His leadership and commitment to justice remain central as he confronts political intrigue and protects the royal family. The 2021 CGI film adaptation reimagines his journey with similar story beats: befriending the Musketeers, battling Richelieu's plots, and developing his relationship with Juliette, while retaining his core bravery and loyalty and expanding roles for Pip and Milady.