#lolth drow

Baldur's Gate 3

Placeholder pic till I have a better one

A whole species who serve (like says in the title) as the evil version of another species.

Sometimes, the specific race doesn't looks like the other race. There's ocassions where the "good" race isn't good (or at least not harmless), otherwise, the evil race have a good individual who's rebelling against the evil in his race (or even the evil race isn't that evil at they seems).

Examples:

Dungeons and Dragons: The Drow are this to the Elves. An estranged elven subrace that has settled the Underdark, infamous for their cruel matriarchal society, dedication to their evil spider-goddess Lolth, and their burning hatred for surface-dwelling elves. 

Mario and Luigi Partners in Time: The Shroobs has this to the Toads, whereas the Toads are a peaceful, kind folk, the Shroobs are warlike and cruel. They even has an counterpart to the Princess Peach in the Princess Shrobb.

Doctor Who: The Daleks are this to the Time Lords. The Revival initially upgraded the Daleks into this for the Time Lords, their equals in power and enemies during "The Last Time War". Note that this wasn't always true, but as the series drew on, it became more and more this way, before being cemented as such in the New Series. However, "The End of Time" demonstrates that the Time Lords have gladly sunk to their level.

The Lord Of The Rings: The Orcs to the Elves. They're both loyal to the Valar and later the Maiar (in the Orcs cases only to one Vala, Morgoth, and later to one Maia, Sauron, the Elves to a whole pantheon of them) and practically act in reverse to each other (Orcs despise sunlight while Elves like it, Orcs destroy the forest that many Elves guard, etc.).

DC Comics: The green martians like the Martian Manhunter are wise, peaceful, and obscenely powerful (with an exception: Malefic, Martian Manhunter's evil brother). White Martians have all the powers of their green cousins, but are monstrously evil (also with, to date, a single exception in Miss Martian).

The Fairly Oddparents: Anti-Fairies, as their names imply, are the blue-skinned polar opposites of fairies in terms of both morality and their respective fairy counterpart's personality. Like fairies, they can have godchildren and grant wishes, but they're only assigned to mean people and they only grant wishes with sinister results, and they have a love of spreading bad luck amongst humans, so their favorite holiday is Friday the 13th.

Star Trek: The Romulans to the Vulcans. They are descendants of a dissident group of Vulcans who had left Vulcan thousands of years ago. For many years the Romulans were hostile towards the Federation, having never truly been defeated nor allied.

Nym

Drow / Lolth