The Twins are unnamed pair of fraternal twins and two playable characters in the video-game "The Cave" but have a dark origin, in addition they are continually talked of as evil by the Cave itself and seem to be motivated purely out of a desire for personal freedom, regardless of who they have to harm in order to achieve said freedom.
The Twins are spoiled children who lived in a boring middle class Victorian House and sought to entertain themselves with progressively more dangerous forms of mischief. This resulting their parents started to become strict to them because their antics were wrong and harmful. The Twins of course, doesn't take it well and decided to kill them to gain their freedom to do what they please disregarding whether it was right or wrong.
As the game have mechanic where each playable protagonists can have either "Good" and "Evil" endings, the route for The Twins' character developement dependant on the player: Had The Twins remained in the evil path, when finally their evil plan went underway, they remain persistent in killing their parents, but it ironically led to their own death as well due to forced to also eat poisoned food. If they went on good path, The Twins realized that they went too far and quickly ruined the poisoned dinner and tearfully apologized to their parents', much to their confusion.
The Twins are made up of a boy and a girl from a Victorian family who continually tried to find ways to murder their parents due to being forced to do chores and obey bedtimes. This however, a petty excuse as they actually dreamt for freedom where they can do whatever they wanted. In fact, their parents actually neither evil nor cruel nor abusive, but rather typical gentle and kind parents who care for them and raised them with care. Even so, their obsession for freedom made them believe that their parents stood on their path.
The Twins also killed their previous dog for barking too much, showing even animals were not immune to their wrath. In a flashback it was shown that they tried unsuccessfully to kill both parents (which the attempts were possibly believed to be mere pranks instead of actual attempt murder) before ultimately finding a means to silence them forever by adding rat poison to their mother's soup : Killing both parents and allowing them to be free to do what they pleased.
Interestingly enough all of the playable characters in The Cave are somewhat morally flawed to the point of being protagonist villains but can obtain either a "Good" or "Bad" destiny by choices they make within the titular Cave. For The Twins, their destinies are:
Forced by their parents to eat their dinner, which resulting the entire family dies a painful, rat poison-induced death.
Finally realising a shred of humanity and errors in their way, they throw the soup to the floor, stopping their parents from eating it. Apologising, they hug their mother and father, who are still somewhat baffled by the attempted parricide.
The Twins have the ability to form spectral clones of themselves.
- As shown in Good ending, neither of The Twins' parents fully aware with how bad their children can be, as they mistaking their earlier attempt murder as pranks.