NOTE: Since this trope reveals a villain being responsible for other events in the series (potentially even after their own demise), expect spoilers.
Villainous Legacies in Western Animation.
- While humans in Adventure Time are long extinct (except for Finn), their "Mushroom War" not only led to the return of magic, but also one of their bombs unleashed the Lich, who proceeded to spread monsters across the planet and kill almost everything. The Alternate Universe shows that even without the Lich, humanity's actions indirectly lead to an apocalypse.
- Avatar: The Last Airbender:
- Fire Lord Sozin in Avatar: The Last Airbender. Avatar Roku's former friend turned evil, he used Roku's death as the chance to start the hundred year war, which resulted in the extinction of the airbenders, save for Aang.
- The Legend of Korra: Yakone was a crime boss who used bloodbending to commit his crimes until Avatar Aang took his bending away. He escaped to the Northern Water tribe, where he fathered two sons, Noatok and Tarrlok. When both sons were revealed to be waterbenders, he put through rigorous training to master his bloondbending to destroy the Avatar. His actions caused Noatok to hate bending and become Amon, while Tarrlok became a corrupt politician who wanted to outdo his father. Both became enemies of Aang's successor Korra, by which point Yakone was dead.
- Batman Beyond: The Joker might be dead, but his legacy (and the mysterious manner of his death) has resulted in roving gangs of criminals in various types of clown costumes and makeup all calling themselves "Jokerz" terrorising Gotham. Not that Old Bruce thought much of them.
- Ben 10: Omniverse: Maltruant's plans for conquest in the final episode cement him as one for the entire Ben 10 franchise, as his arriving on Earth in the past, with Ben, Rook and Skurd following him, are why pre-series Vilgax becomes interested in a device that grants the wearer shapeshiting abilities.
- Castlevania (2017):
- The Bishop gets killed quickly by one of Dracula's minions. However, it is clear that his murder of Lisa Tepes still influences the story, even after he died.
- Dracula is killed at the end of Season 2. For the next two seasons, every other antagonist is either taking advantage of the resulting Evil Power Vacuum or trying to resurrect him.
- Final Space:
- Although the Lord Commander is killed by Nightfall, his actions during the first season have a lasting impact before his resurrection: he's caused the Earth's destruction, which in turn sets off Todd's vendetta against Gary, and his actions also led to Quinn getting trapped in Final Space, with reaching Final Space to get her back being the Team Squad's primary mission throughout Season 2.
- Although the evil Titan Oreskis is killed in Season 3 after only a couple appearances, before his death, he deals a wound to Bolo that infects him with Invictus and enables the latter to break his mind later on. This in turn enables Invictus' scheme to push Ash down a Start of Darkness to progress further.
- Gravity Falls: Nathaniel Northwest's refusal to keep his word to the people of Gravity Falls resulted in the Lumberjack's ghost haunting his descendants. His influence even spread for generations into the modern day Northwest family, as they're a bunch of greedy, egotistical Abusive Parents that made Pacifica the way she has been up to this point.
- Jackie Chan Adventures: Shendu's seven Demon Sorcerer siblings appear only in Season 2 and remain imprisoned afterwards. However, in Season 5, it is revealed that the symbols used by the Eight Immortals to banish them were corrupted with some of each demon's chi left stored in the symbols. In Relics of Demons Past, the chis are activated by an alignment of stars, and Drago sets out to claim them in order to become powerful enough to conquer the Earth. It's embellished by how each demon chi causes its new host to look more and more like the demon which that chi originated from if it isn't removed quickly.
- My Little Pony: Friendship Is Magic:
- Nightmare Moon is restored to Princess Luna at the start of the series. Nearly every episode focusing on Luna has her deal with the bad reputation and guilt over her actions.
- Played with in the Season 3 opener. King Sombra is still very much around, but too busy being held back by a barrier to do anything directly. So instead, most of his actual, onscreen threat is merely a Race Against the Clock to bypass all the curses and traps he left behind during his original reign before the barrier eventually collapses. Yet he still manages a Near-Villain Victory — he was just that Crazy-Prepared back then.
- The Season 4 opener has one of (the since reformed) Discord's old plans finally activate after a long delay.
- "Castle Sweet Castle" is all about Twilight Sparkle dealing with her old home being destroyed by Lord Tirek, who's been re-imprisoned in Tartarus by this point.
- The Smurfs' enemy Gargamel seems to have come from a long family line of unscrupulous characters. In the final season of the cartoon series, where the Smurfs are constantly traveling through time, different incarnations of the villain would appear, such as showing him as an Indian fakir, a Russian peasant, or a Spanish bullfighter. In one of the earlier episodes of said season, Papa Smurf theorizes that all these similar-looking men must be ancestors of the evil wizard of their present time.
