Molly

Molly is Angel Dust's twin sister and Arackniss's younger sister. She has yet to make an appearance in Hazbin Hotel.

Appearance
Like her twin brother, Molly is brightly colored, has four arms, and has three spots under her eyes to resemble how a spider normally has eight eyes. She has big voluminous hair that is supported by a hairband, she wears a double shoulder-padded suit with sleeves that extend to the palms of her upper set of hands, she wears striped gloves that reach the arms of her lower pair of hands. Unlike Angel, she doesn't have additional sets of arms but instead has two sets of legs.

Angel Dust
Angel is Molly's twin brother. It's unknown what sort of relationship the two have outside of being blood-related.

Vivzie stated that their relationship is positive and that she can't say much because a lot of that is after the Pilot.

Arackniss
Arackniss is Molly's older brother. It's unknown what sort of relationship the two have outside of being blood-related.

Henroin
Henroin is Molly's father. It's unknown what sort of relationship the two have outside of being blood-related.

Mother
Molly has a mother, but their relationship outside of being blood-related is unknown.

Trivia

 * Though she has yet to appear, Vivienne confirmed Molly is canonically Angel Dust's sister. She is still in development but is tentatively planned to appear later in the series, along with Angel Dust's other family members.
 * She may appear later in the series, or at the very least be referenced; Vivienne said in her live stream that she wants Molly in the show at some point. Furthermore, her design may undergo some changes prior to her planned debut.
 * Angel and Molly are fraternal twins and not identical twins.
 * She is not a demon, nor is she in Hell.
 * When asked if Molly is her real name or the name she has in Hell, Vivziepop said that Molly is her real name.
 * Her name is a reference to the drug Molly, also known as ecstasy. This might also reference her personality and cheery appearance, as Ecstasy causes users to feel immense emotional pleasure, energy, empathy, and altered sensations.
 * Molly, and in extension, Angel Dust’s birthday are under ambiguity. According to Vivziepop, she initially recalled it as April 1st, but later revealed she does not remember the true date.