Marty Stu, however, is usually restricted to being a creature of action since men who do not take an active role in dramatic events are unmanly and, by definition, not perfect (Non-Action Guy tends to be looked upon with disdain). So Marty Stu is the personification of action, action and more action. Or, if he is of an intellectual bent, he thinks his way through problems, inventing whole new branches of science and technology in the process. In contrast to Mary Sue who has been freed to play an active and/or passive role, Marty Stu is almost never seen taking on his sister's old school Purity Sue role: passive motivator of others through his purity, beauty and helplessness. When he does, it is almost exclusively the territory of wimpified Possession Sues in yaoi fanfic.

Marty Stu is devastatingly handsome (or if not, possessed of a strange, saturnine magnetism) and desired by all significant women, yes, but romance is not likely to be the main dish. He's an unstoppable fighter, a rogue agent, a fearless freedom fighter, a master of disguise. However, as times have changed, just as Mary's acquired a bratty temper, Marty's had the occasional opportunity to show his softer side.