Molly

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

Appearance
Molly, like her twin brother Angel Dust, is brightly colored and has three spots under her eyes to resemble how a spider normally has eight eyes. Unlike Angel Dust, who possesses six arms, two being hidden, and two legs, Molly possesses four legs and four arms.

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.

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

Vivziepop stated that their relationship is positive, but she can not say much because a lot of that is after the pilot.

Arackniss
Arackniss is Molly's older brother. It is unknown what sort of relationship the two have outside of being blood-related, although, it is implied to be negative.

Unnamed Father
Molly is confirmed to have a father, but, it is unknown what sort of relationship the two have outside of being blood-related.

Unnamed Mother
Molly is confirmed to have a mother, but, it is unknown what sort of relationship the two have outside of being blood-related.

Trivia

 * Though she has yet to appear, Vivziepop confirmed Molly is canonically Angel Dust's sister. She is still in development, but is tentatively planned for the series, along with Angel Dust's other family members.
 * She may appear later in the series, or at the very least be referenced; Vivziepop 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.
 * In "Welcome to Heaven", one of the angels bears a striking resemblance to Molly's previous design. However, it is currently unknwn whether it is indeed her.
 * 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 may be 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.
 * Additionally, she is the only one in Angel's family to keep her human name after death.
 * Angel Dust, and by extension Molly's birthday was once under some ambiguity. Vivziepop felt that Angel Dust's birthday was April 1st, although at the time she couldn't say for certain, however, the following year she wished Angel Dust a happy birthday on April 1st in another Tweet.
 * On April 1st, 2023, the official Hazbin Hotel Twitter released a sketch confirming Angel Dust's birthday is on April 1st.