Token Motivational Nemesis

You've seen it a dozen times since Batman in the 1930s:

A villain traumatizes the hero in the opening pages of a comic book's first issue, possibly scarring him physically. Driving the hero to train him/herself into the very definition of a perfect warrior/detective/vigilante/wizard/whatever you will, this scumbag quite literally made the hero what he is today.

One would think that a villain of such importance to the very mythos of the story would be a continue to be a source of character motivation and story importance...

...only that by the final pages of the first issue (or at the end of the first story arc), having served his purpose of making the hero the way he is today, he is unceremoniously disposed of, and almost invariably never spoken of again.

This phenomenon occurs in many retrospectively popular works, which like all fiction must compete in a market that does not give second chances. Particularly in the first productions of many comic and manga authors, one is encouraged to finish his story as soon as possible in case it proves to be unpopular, so the publishers can have an easier time cutting the losses. Only when the successful sales figures come in are the authors forced to bear the awkward responsibility of expanding a story beyond the scope of the now already-dead villain that has created it.

Most Token Motivational Villains are Starter Villains, although that's not always the case.

Anime and Manga

 * Shin, Kenshiro's romantic rival-turned-nemesis in Fist of the North Star, was the one who defeated him in combat, engraved the seven scars on his chest, and stole Yuria, the love of his life, away from him, leading Ken to his quest for revenge. Shin then goes on to amass a huge gang and declares war on Kenshiro...until he is defeated by the end of the manga's tenth chapter. The cover of the second Jump Comics volume doesn't even try to hide Shin's literal downfall.
 * The TV series did give Shin a bigger role by arranging the order of events of the first few story arcs, placing the final battle between Kenshiro and Shin a bit later than it had originally occurred. As a result, Shin gets more henchmen besides Mr. Heart and the other three playing card themed thugs who worked for him in the manga and his pining over Yuria is given a bit more focus as well. He also gets one good fight scene on the episode before his battle with Ken.
 * The original movie on the other hand, gave Shin even less things to do than what he did in the manga. After defeating Kenshiro, Shin spends almost all of the movie walking around in his castle and giving orders to his lackeys. When Kenshiro finally arrives at Southern Cross to confront Shin, he finds out that Shin has already been defeated by Raoh, his more iconic rival.
 * Nakatsukasa Tsubaki's brother Masamune in Soul Eater.
 * Higuma the Bear in One Piece. He didn't exactly fight anyone, but he nearly killed the then overconfident main character, only to be forgotten entirely at the end of the ark. The fact that he was eaten by a sea monster may have had something to do with it.
 * Subverted in Itsuka Tenma no Kuro Usagi: Hinata seems to be one for Gekkou, setting up the latter's entire motivation to get to where he is today, only to be killed off at the end of the second episode. Yeah, not so much...

Comic Books

 * Joe Chill, the mugger who murdered Bruce Wayne's parents, is possibly the most well known example of this trope. While Batman's origin story was first shown in Detective Comics #33 (published November 1939, a few months after his debut), the true identity of the mugger was not revealed until Batman #47 (June 1948, almost ten years later), where he was unceremoniously killed by his very own henchmen when they learned he was indirectly responsible for the birth of Batman. In the post-Zero Hour continuity, the writers at DC made the identity of the mugger unclear, with the rationalization that since Batman never found out his parents' murderer, any criminal he catches might as well be the one who did it. However, the Infinite Crisis storyline retconned the mugger's identity back to being Joe Chill.
 * This story was the basis for the Batman the Brave And The Bold episode "Chill in the Night". The episode borrowed much from #33, but upped the ante. Joe was an arms dealer auctioning weapons on the black market, replaced his henchmen with Batman's Rogues Gallery (who were attending the auction), and
 * Deconstructed in Batman Begins. Joe Chill is killed by a mob hit before Bruce can take his revenge. Being denied vengeance motivates him to become Batman, with the added bonus of Rachel guilting him into swearing off guns.
 * The Tim Burton film version turned Jack Napier, the man who would become Joker, into the murderer of Bruce Wayne's parents, presumably to add more chemistry to the Batman/Joker rivalry. However, the Joker got killed in the first film and never appeared in any of Burton's or Schumacher's sequels.
 * Mr. Carradine, the thief who murdered Peter Parker's uncle Ben Parker. He came back for a second appearance in the seventies, and died of a heart attack when Spidey revealed his identity.
 * And he did not even get a name until the 1990s, when his daughter appeared in a storyline that involved her with Ben Reilly during the Clone Saga.
 * In the third movie, Uncle Ben's murderer was actually Sandman, a member of Spidey's Rogues Gallery in the original comics. However, the killing was accidentally provoked by the burglar originally thought to had been Uncle Ben's murderer, who was the Sandman's lackey.
 * And in The Spectacular Spider-Man . This version turns out to have never intended to kill anybody, and guilt has made him repent in prison.
 * Similarly, The Fixer who turned Matt Murdoch into Daredevil dies of a heart-attack by the end of the first volume.
 * The Movie replaced him with the Kingpin, doing a routine hit on his way to the top.
 * Frank Miller's re-telling of Daredevil's origin, entitled "The Man Without Fear," has The Fixer ordering the Kingpin (at that point, his main enforcer) to kill Matt Murdoch's father. Later in the miniseries, Kingpin takes control by killing the Fixer.
 * Marie L'Angelle in Preacher (Comic Book), Jesse Custer's grandmother who made his childhood a living hell, is introduced in the beginning of the second volume but dies halfway through the book. Her influence, however, radiates on a while longer -.
 * In the original run of Teenage Mutant Ninja Turtles, The Shredder, the evil ninja who would serve as the Turtles' archenemy in later versions of the saga, turned out to be this, being killed by the Turtles in the first few issues.

Films

 * Obadiah Stane/Iron Monger in the Iron Man movie; he is revealed as the movie progress to be the one who hired the Ten Rings to kill Tony Stark, such indirectly causing the incident that changed Stark's vision over life and led him to become Iron Man. Despite this, he doesn't survives the first movie, and is never mentionned again in the second Opus. Ironically enough, this version of him led the character to be promoted in the fans' eyes, and he is made part of the Big Bad Ensemble in Iron Man: Armored Adventures.

Video Games

 * from the first Ace Attorney game, whose murder of 15 years earlier turned pretty much all of the recurring cast's lives around, be it directly or indirectly. He is only mentioned a few times in the second and third games.
 * Similarly, from the same game. He kills, an act that is responsible for many characters' first meetings and is the main reason Maya chooses to participate in the series at all. Phoenix gets him arrested, and everyone promptly forgets he ever existed. Even when the third game introduces a new character whose entire characterization is based around that murder, he barely acknowledges the murderer.

Western Animation

 * Mr. Fixx killed Terry McGinnis' father and then died in the first episode... maybe... Of course Derek Powers ordered the hit, and was still around to be the target of Terry's vengeance. However, Powers disappears at the end of Season 1 and never returned in any of the following seasons, despite the possibility being left open.
 * Hakon, who massacred Goliath's clan in Gargoyles is killed in the second episode of the series and rarely mentioned again. He does return as a ghost in two later episodes but in the first the focus is mostly on the Captain of the Guard and the second is a comedic Breather Episode with little overall importance to the series.