A cause of many or most of the bad happenings in a story, and often the main cause of most or all of them. A Big Bad could be a character with Evil Plans or it could be an omnipresent situation, such as a comet heading towards the Earth. In a serial story, the Big Bad exerts an effect across a number of episodes, even an entire season. Known as the Shadow in The Hero's Journey.

This trope is not a catch-all term for the biggest, ugliest villain of any given story. In fact, it doesn't have to be a villain at all, as stated earlier. If it is a villain, though, it should be identified correctly; the badass leader of the outlaw gang that causes the most personal trouble is not the Big Bad. The railroad tycoon who is using the gang as muscle is the Big Bad. The Man Behind the Man is very common for this trope, leaving the reveal of the big bad as The Chessmaster behind it all and proving themselves far more clever and resourceful than the Villain of the Week. Sometimes the Big Bad is the grand enemy of an entire franchise. At other times, the Big Bad is an Arc Villain who causes trouble for a period of time only to be replaced by another Big Bad.

When assessing the entire story, a Big Bad will be at the center of the Myth Arc rather than just any Story Arc, but this a generalization. When you look at a seasonal plot, a major Story Arc or long form narrative work (such as a Doorstopper or Movie Multipack), the Big Bad will be the main cause of the conflict, causing all the strife and struggle in one form or another.

The term "Big Bad" was popularized in Buffy the Vampire Slayer (though itself inspired by The Big Bad Wolf). The structure of Buffy placed the Big Bad as being crucial to the Half-Arc Season, half the episodes are filler dealing with unrelated enemies while the other half involved the ongoing Myth Arc with the Big Bad. They would spend some time introducing new villains and gradually building around interconnected plot points which would often hide their identity at first or lead to them taking center stage as certain events unfold, leaving it a mystery who they were actually dealing with but would become a defining characteristic of that season. By season six some characters would refer to themselves as "the Big Bad" (although they would be usurped by another force, becoming more of a Big Bad Wannabe).

If a show has a series of Big Bad jeopardies, they can function like a series of Monsters of the Week that take more than one week to finish off. If there is a Legion of Doom, you can expect the Big Bad to be involved somehow. They're probably sorted by power, with the strongest for last, following the Sorting Algorithm of Evil.

In tabletop gaming circles, the Big Bad is often referred to as the BBEG (Big Bad Evil Guy).

Evil Overlord, Diabolical Mastermind, The Chessmaster, Arch-Enemy, The Man Behind the Man, and often Manipulative Bastard are specific types of villains who are liable to show up as Big Bads. If they're a Magnificent Bastard or Hero Killer, the good guys are in big trouble. The heroic counterpart of this character is the Big Good, who will very often be the focus of this character's attention over The Hero at the beginning of a series. If a work of fiction is conspicuously lacking a Big Bad, it may be a case of No Antagonist.

See also Big Bad Duumvirate for two (or more) Big Bads working together. Sometimes a Big Bad will get their start as a servant to another villain — if that's the case, they're a Dragon Ascendant. If the character who fills the role of Big Bad in most meaningful ways is nominally subordinate to someone else (someone significantly less menacing by comparison), they are a Dragon-in-Chief. If the story has many Big Bads at once who don't work together, see Big Bad Ensemble. The Big Bad Shuffle occurs when there are multiple candidates for the Big Bad position. If the Big Bad doesn't start out as bad but develops over the course of the story, it's Big Bad Slippage. If the Big Bad of one section of a work doesn't die on being defeated and stays around as a character in a different plot role (reformed or not), that's Ex-Big Bad. Some may require you to Hit Them in the Pocketbook. If a villain is literally a Big Bad, see Evil Is Bigger.

The Big Bad of a story is not always the most powerful or oldest existing evil force. Perhaps an evil presence along the lines of an Eldritch Abomination overshadows the work's setting, but is mainly divorced from the story's events — that would be the Greater-Scope Villain. A Big Bad who seeks the aid of a Greater-Scope Villain, possibly by freeing a Sealed Evil in a Can in the hopes of invoking Summon Bigger Fish might find themselves very much on the end of Blatantly Self-Defeating.

It is one of the most well-known tropes on the TV Tropes community, being the first to have over sixty thousand wicks, and is currently the most wicked trope on the site. This is probably because it's incredibly common.

May overlap a Conclusive Confession, especially if their arch enemy is a Great Detective. See also Occupational Hazard for the various fates that may await them, their underlings, and their adversaries.

If a Big Bad accompanies Ominous Clouds, a hero is shown to be triumphant with a Cloud-Clearing Burst.

Examples:

• Anime & Manga
• Comic Books
• Fan Works
• Films — Animation
• Films — Live-Action
• Literature
• Live-Action TV
• Pro Wrestling
• Tabletop Games
• Video Games
• Visual Novels
• Webcomics
• Web Original
• Western Animation
• Other Media

Related tropes:

• Arc Villain: The Big Bad of a Story Arc, but not of the story as a whole. They may or may not be working for the overall Big Bad.
• Arch-Enemy: The main villain of the story is usually (though not necessarily always) the primary nemesis of the main hero.
• Big Bad Duumvirate: There's two Big Bads working together! They might not get along, though.
• Big Bad Ensemble: Multiple Big Bads in the same story, but not necessarily on the same side. They still might not get along.
• Big Bad Friend: The Big Bad was once such good friends with one of the main characters.
• The Big Bad Shuffle: It's a toss-up as to who the Big Bad is.
• Big Bad Slippage: The Big Bad slowly becomes ever more evil.
• Big Bad Wannabe: The villain isn't as big of a threat as they seem or try to be.
• The Big Bad Wolf: The Trope Namer of "Big Bad" is the evil Wolf from classic Fairy Tales, such as The Three Little Pigs and Little Red Riding Hood.
• Demoted to Dragon: The current Big Bad being revealed as the Dragon to a bigger threat.
• Dragon-in-Chief: The de facto Big Bad is subordinate to another, lesser villain.
• Ex-Big Bad: You either die a hero or live long enough to see yourself stop being the (main) villain.
• Evil Overlord: The classic Big Bad for many works of High Fantasy and similar adventure tales is an evil dictator/emperor/warlord who runs The Evil Empire.
• Final Boss: The main villain also tends to be the final enemy for the heroes to defeat in the story's climax. In the context of video games (where the term comes from), then the Big Bad is usually the last (and most likely the toughest) Boss Battle for players to beat.
• Greater-Scope Villain: A Bigger Bad who's (in)directly responsible for most of the story's conflict, but their role isn't quite as prominent as the actual main antagonist.
• The Heavy: The villain responsible for the obstacles the hero has to overcome. This is usually the role played by The Dragon but there have been a couple times where the Big Bad plays this role.
• The Man Behind the Man: The supposed Big Bad is secretly working for the real Big Bad.
• The Man in Front of the Man: Inverse of The Man Behind the Man. The real Big Bad pretends to work for the supposed Big Bad.
• Non-Action Big Bad: A Big Bad who doesn't fight directly, instead relying on their underlings to do their dirty work.
• Returning Big Bad: After a period of absence, a previous Big Bad returns to the story and acts as the main villain again.
• Vile Villain, Laughable Lackey: A duo consisting of a serious villain with a humorous subordinate.
• Villainous Friendship: When the Big Bad is good friends with The Dragon.
• Weak Boss, Strong Underlings: When the Big Bad is actually less physically powerful than their Evil Minions and Mooks are.