The Twins are a pair of lesser-antagonist Variants who were patients at the Mount Massive Asylum. Typical of many Variants, they seem driven to destroy Miles Upshur. They are followers of Father Martin's cult.
The Twins are two brothers who are followers of the cult leader Father Martin. They often discuss murdering Miles Upshur and consuming both his liver and his tongue. They are seemingly very loyal to Father Martin, going so far as attempting to suppress their murderous urges out of respect for him, although they ultimately fail to do so.
The Twins are calm, intelligent and well spoken but are clearly insane, with both twins openly expressing murderous and cannibalistic desires, making them very dangerous. They also walk around the asylum completely naked. The Twins are very cold and calm in their methods of murder and rather than hastily chase and yell, they will silently and calmly walk towards Miles. They are also a lot more methodical than most Variants and use tactics, such as encircling and ambushing Miles from front and behind in an enclosed corridor. They can also open and close doors unlike most other Variants, who will simply bash them down. They use a pair of large, machete like blades as their main weapons of murder. They are able to perform an instant kill on Miles with these weapons if they get close enough, first by stabbing him through the gut and then decapitating him with a second blow.
Miles first encounters the Twins at the beginning of the Prison Block level. Here, they discuss killing him and taking his tongue and liver, but decide that it would be impolite to do so due to Father Martin instructing them not to harm Miles, showing just how much influence the Father has over them. However, they later decide that they've suppressed their urges for long enough, and begin to hunt Miles despite Father Martin's wishes. Soon afterwards, near the Prison Showers, they trap Miles in a corridor from front and behind, forcing him to climb out of an adjacent window to escape. They then have a somewhat humorous discussion and consider pulling Miles back inside and killing him, but decide not to for some reason. Throughout the rest of the game, Miles encounters them a few more times. Notably in the Female Ward, where they again ambush him in the darkness, this time from behind a set of closed double doors. In their final appearance, they are seen as acting doormen at the chapel during Father Martin's crucifixion and have ceased all hostilities with Miles, even respectfully opening and closing the chapel doors for him.
They are briefly seen in the Whistleblower DLC in a cameo appearance of sorts, in a scene which very much mirrors Miles' first encounter with them. They are seen by Waylon Park from behind a wire fence in the prison yard and openly discuss in front of Waylon their desire to kill and eat him.