 
Porthos is a member of the Three Musketeers in Alexandre Dumas pere's novel LE TROIS MOUSQUETAIRES/THE THREE MUSKETEERS (1844). A giant of a man, Porthos is a pompous Musketeer indulgent in lavish finery, drink, and women. Although a figure of comedy, he is a skilled swordman loyal to his friends. Like Athos and Aramis, Porthos makes a dueling enemy and then a friend out of D'Artagnan.
Like Aramis, Porthos sometimes suffers neglect in the many film versions of the novel. His character arc is sacrificed in favor of D'Artagnan's (and Athos') adventures. The same treatment occurs in the many adaptations of THE MAN IN THE IRON MASK.
Like Athos and Aramis, Porthos is quickly defeated and impersonated by the Three Lackeys in the 1939 Twentieth Century-Fox/Ritz Brothers version.
The 1966 BBC Serial faithfully gives Porthos his own plotline from the original novel.
The 1974 Richard Lester version shrinks Porthos' tall height to a shorter one. He is the major comic relief of the group, making mistakes in battle (losing his sword, accidentally sealing himself within enemy lines). Nevertheless, such stupidity is also complemented with clever thinking (staging a mock duel in a tavern to steal food, rescuing Constance with stilts, etc.). His closest friend in the Musketeers is Aramis, with whom he has discussions about religion and service.
The 1993 Disney adaptation also faithfully portrays Porthos' pomposity (he boasts about gifts from the Empress of America and the Tsarina of Tokyo) and clever inventions.
The 1998 adaptation of THE MAN IN THE IRON MASK gives Porthos a humorous obsession with suicide. His attempt to hang himself is fortunately unsuccessful thanks to Aramis.