Frankie Stein (voiced by Kate Higgins, singing voice done by Allison Iraheta) is the daughter of Frankenstein's monsterand his bride and the granddaughter of Victor Frankenstein's (since Victor had built her parents). Frankie is the sweetest, heartiest girl at Monster High, and believes that everyone's flaws make them unique. Starting at 15 days old, she is also the youngest student at Monster High. She is very optimistic and never gives up in the face of adversity. However, since all of her prior knowledge about teen relationships came from magazines, she can be a bit naive and inexperienced in teenage issues.
Being a Frankenstein's monster herself, she has light green skin and her body is literally stitched together. Because of this, her arms and legs can be detached from her body and still move, which she has used several times to help her friends. Early on, her limbs often flew off accidentally, but she has gotten much better at controlling them. Along with this, she is powered by lightning and has to be recharged every night as seen in "New Ghoul at School". She can also emit lightning for self-defense and to power electronics in a pinch, but most often ends up accidentally shocking people. Her eyes are two different colors, the right one being blue and the left one being green, and her hair is white with black streaks.
She has romantic feelings for Neighthan Rot as seen in "Monster High: Freaky Fusion", which seems to be mutual.
Clawdeen Wolf (voiced by Salli Saffioti) is the daughter of the Werewolf. Clawdeen is sixteen years old and comes from a rather large family, though she has only had three known siblings seen so far (Clawdia, Clawd and Howleen). She also calls herself "The Alpha Wolf of Style". Her best friends are Frankie Stein and Draculaura (whose father sometimes objects when Clawdeen visits her). She complains about her younger sister Howleen (with whom she shares a bunk bed) because Howleen is constantly chewing on her shoes, borrowing her clothes, and wiping her nose on her jackets.
Clawdeen has trouble keeping her werewolf side in check; this side of her can emerge at the sight of a full moon or any other similarly bright light source as exemplified in the episode "Talon Show". She is quite strong, being seen holding up at least three ghoulfriends in cheerleading sessions. Clawdeen dreams of owning her own fashion design brand, plays on the soccer team, and in the webisodes, it is shown that she enjoys track and field. Clawdeen disliked Cleo de Nile at first, because she incorrectly thought that Cleo had cheated on Clawd with Deuce Gorgon. After Clawd explains to her that his breakup with Cleo was in fact mutual, Clawdeen and Cleo become frenemies soon after, even though they are both on the fearleading squad. Clawdeen hated the idea of Draculaura and Clawd dating and tried to stop it, even becoming mean and a bully in the process, but, eventually she accepted she was wrong, apologized, and finally approved the relationship.
She has a purple pet kitten named Crescent.
Cleo de Nile (voiced by Salli Saffioti) is the daughter of the Mummy named Ramses de Nile and the younger sister of Nefera. Her father is a mummy. She is 5,842 years old. Her clothing motif is bandages and hair gold. Cleo does not get along with Nefera because Nefera uses every opportunity she can to humiliate her younger sister and get her into trouble with her father.
Cleo is considered spoiled rotten, but sometimes help her friends if necessary. Cleo does have a good heart, but hides it behind her popularity. Cleo is also the tallest girl out of her main group of friends. She is the leader of the fearleading team. Her true love is Deuce Gorgon.
Draculaura (voiced by Debi Derryberry) is a pink-skinned vampire with black and pink hair who is the daughter of Count Dracula. Her primary trademark name was originally Ula D, and now is a shortening for Draculaura, while she is called Lala for short in the books. The character was initially 1,599 years old and turned 1,600 in the webisode "Party Planners" along with Frankie and in the film Why Do Ghouls Fall In Love, with Mattel releasing a doll line based around her birthday.
Despite being a vampire, she is a vegan who consumes fruits, vegetables and "a lot of iron supplements" instead of blood. She is dating Clawd Wolf, Clawdeen's older brother, and has a pet bat named Count Fabulous, and she absolutely adores pink. Draculaura is one of the most popular monsters at school, due to her friendliness. In Frights, Camera, Action, Draculaura ends up getting her vampire powers unlocked after helping Elissabat.
Draculaura is a sweet, caring, animal-loving girl who dresses her bat, Count Fabulous, all girly-like. Draculaura is a sweet and loving girl and her favorite class is creative-writing. She faints when hearing the word "blood". As the book series progresses, Draculara is referred to as a vegetarian vampire rather than vegan, and the description carries over into later books, the animated series, both show and CGI TV specials.
Ghoulia Yelps (vocal effects provided byAudu Paden) is the bespectacled daughter of a zombie couple and Cleo's personal assistant and best friend. She is also a zombie. She has a pet baby blue owl named Sir Hoots-a-Lot. The smartest ghoul at Monster High, Ghoulia is a shy and bookish girl, but Cleo de Nile refuses to let her be the wallflower at a party. She can only speak in the zombie language (moans and groans) due to physical limitations that all zombies have. Ghoulia's social life has improved greatly since befriending Cleo. She is the shortest girl at Monster High. Part of this may be because as a zombie, she never stands up straight.
Ghoulia has a romantic interest in Slo-Moe, a tall male zombie on the chess team. Ghoulia is well-known to be a hardcore fan of "Dead Fast", an in-universe comic book series. She also has a love for the game of dodgeball. Her favorite color is red.
Lagoona Blue (voiced by Laura Bailey in 2010-2015, Larissa Gallagher in 2016-Present) is the daughter of the Gill-manWade Blue and a sea nymph, who is all fish. She is a kind and loving girl, with a tomboyish style to her clothes, and has problems with Gil's parents due to her sea-monster heritage. However, they started to like her only for being a freshwater monster when she turned into one from Howleen's wish in "13 Wishes". Lagoona is a kind and friendly ghoul who loves swimming. She also loves Gloom Beach and playing water-volleyball. She is dating Gillington "Gil" Webber. Her childhood best friend was Kala Mer'ri, who turns out to be the daughter of the Kraken.
