Successful

Antagonists and villains who win against the hero (or other rival villains) and/or are successful in their ultimate goals.

They are, usually, the opposite of Incompetent antagonists/villains (who do not succeed in anything), though some Incompetent antagonists/villains can still be successful either with a huge stroke of luck, with the help of much more competent evildoers, or by learning from their own mistakes to become better.

It should be noted that for some antagonists and villains, their goal was not to kill the main protagonist. Notably, successful villains are very common in many modern-day horror movies (e.g. Freddy Krueger, Jason Voorhees, Godzilla, Kayako Saeki, etc.) as well as some tragic fictional works (e.g. Padre Dámasore, Iago, etc.) in which many of these antagonists and villains succeeded in killing the protagonist in the end.

In many works, a successful antagonist/villain can be a Protagonist since protagonists are known for winning in the end.

Though these two categories often overlap, this is not to be confused with Karma Houdinis, as these antagonists and villains, despite their success, can still be defeated later, usually at the end of the story if their success occurred at the beginning or middle of it, or in a sequel since some antagonist/villain victories open the doors for sequels (e.g. Archibald Snatcher succeeded to get his White Hat and taste cheese, but his allergy caused him to explode, Scar finally becoming the King of the Pride Lands after killing his brother and banishing his nephew, only to be dethroned by said nephew and killed by his hyena henchman at the end of the movie or Koba who succeeds to start a war between humans and apes but is killed by Caesar) and conversely, they cannot be ever defeated despite their failure. In some cases it may even be that their death is part of the reason that they were successful in the first place as it was all part of their plan (e.g. The Joker from the Injustice universe, who managed to push Superman into killing him and as a result transform him into a monstrous tyrant, and John Doe, who kills David Mills's wife out of envy and then corrupts Mills into killing him and turning into the sin of wrath to complete his seven deadly sins project). However, some antagonists and villains that are successful can also be Karma Houdinis if they are successful enough, such as Rustal Elion.

Also, sometimes these antagonists and villains finally succeed in their goals, but not in the way they expected (e.g. Wile E. Coyote finally catching the Road Runner, but only when he became too small to eat him, Erik Killmonger convincing Black Panther to open Wakanda to the rest of the world, but in a much more peaceful way, Chef Skinner getting Gusteau's closed for rat infestation, but Linguini and Remy are still able to open the Ratatouille, Tai Lung obtaining the Dragon Scroll but failing to realize the significance behind it and Max Mordon obtaining immortality, but in the form of an undead mummy) or they didn't get to enjoy it (e.g. Marty Wolf turned Big Fat Liar into a critical and financial hit but lost his job and fame for plagiarizing Jason Shepherd's work, Brad Gurdlinger got Pablo Chacon arrested and removed from the drug business but was taken into custody as well, Thomas Magruder found the lost city of Quivira, but failed to steal the gold and died trying to kill Colton).