The Elements of Insanity are the corrupted version of an alternate universe Elements of Harmony. The group consists of Applepills, Brutalight Sparcake, Derpigun, Fluttershout, Pinkis Cupcake, Rainbine, RariFruit each of which contain the souls of some TF2 Freaks (with the exception of Applepills).
Brutalight Sparcake is the main leader of the Elements of Insanity though RariFruit or Fluttershout have been known to take over Brutalight's duties. The Elements of Insanity are divided into groups of two which include the Cutie Mark Creep and the Demented Six.
Applepills, Brutalight Sparcake, Derpigun, Fluttershout, Pinkis Cupcake, Rainbine, RariFruit form the Demented Six though they are actually seven in total but because Derpigun's former self, Derpy Hooves or Ditzy Doo was never actually in the real Elements of Insanity.
The Cutie Mark Creeps are Creepy Belle, Karateloo, Francie Bloom and are basically the Cutie Mark Crusaders with the souls of TF2 Freaks (though Francie Bloom is not based on one).
The Demented Six Edit
Main article: Brutalight Sparcake
Brutalight Sparcake acts as the Elements of Insanity's leader despite being created by the Elements of Insanity themselves. She contains the souls of TF2 Freaks Weaselcake and Christian Brutal Sniper.
Main article: RariFruit
RariFruit more or less sometimes acts as the leader of the group because of her behaviour and that she was the first of the Elements of Insanity to be possessed. The Freak TF2sona of RubberFruit inhabits her.
Main article: Fluttershout
Fluttershout, the hothead (and the loudest) of the group, FLuttershout along with RariFruit have been known to take over Brutalight's duties. She contains the Freak TF2sona of GAYPENlS.
Main article: Derpigun
Derpigun like the soul she inherits which is Pyrogun is a cyborg pegasus akin to that of Rainbine (though she has two built-in weapons unlike Derpigun). Like her the soul that is within her she is clumsy though she might inherited from herself.
Main article: Rainbine
Rainbine is the boaster of the entire group and is overconfident with herself much like the original Rainbow Dash.
Pinkis Cupcake has within her the soul of one of the most powerful and legendary TF2 Freaks which is Painis Cupcake (not the Original Vagineer, dummkopf). She represents the element of bloodlust.
Applepills is the only member in the group to not have a soul of a TF2 Freak but rather a parody of Louis from the video game Left 4 Dead 2.