Mabel Gleeful

Mabel Gleeful is one of two main antagonists of the Disney's 2017 animated film, Gravity Falls: The Movie.

Personality
Like his sister, Dipper has a lust for power and enjoys the pain of others. He's often seen to be either cold and unfeeling, or simply disgusted by the affection or caring of others. Seemingly, the only person he shows any sign of actual care for is his sister/partner Mabel, but even that has its limits.

Dipper is extremely intelligent and sly, being able to fool the town into believing him to be a kind and benevolent young man. He has little trouble manipulating others into doing or getting what he wants. This makes him a great threat, with or without his amulet.

However, unlike his sister, Dipper is seen to be slightly more stoic, serious and more disgusted by those he deems pathetic or weak, instead of sinisterly amused like Mabel is shown to be.

Dipper Gleeful
Dipper is Mabel's twin brother and partner in crime, whom she probably 'cares' the most for. At the very least, she respects him and his powers. She enjoys spending time with him, whether it's torturing Will and their victims, or simply sitting at home and discussing their performance with him. She does love Dipper as a brother and partner. In some versions she and Dipper have a incestuous relationship.

She doesn't like it when he talks to Pacifica; it's unknown if it's because Mabel's jealous that Pacifica will steal Dipper from her, or she simply finds Pacifica too annoying for Dipper.

However, when they are torturing their victims, Mabel gets annoyed when Dipper is telling her to stay on task and calls him a 'killjoy', which Dipper hates. However, there are times when Mabel believes her brother to be a 'psycho' and too much for her. Despite this, she has never completely retaliated against him; whether this is from actual sibling love, or from doubt in her ability to defeat him, is unknown.

It has also been shown that Dipper's power and sinister amusement has made Mabel somewhat fearful before.

Pacifica Southeast
Mabel constantly teases Pacifica Southeast, but Pacifica still tries to show kindness to her. However, this doesn't stop Mabel. Later on, she begins seeing her as a threat, as Pacifica begins to hold influence over Dipper, which causes Mabel to start to hate her. In reality, she is jealous of Pacifica's life and personality, but Mabel never really admitted that.

Grenda and Candy
Little is known about her friendship with Reverse Grenda and Candy, only that they tend to cling to her out of either fear or enjoyment. Either way, they will happily assist in physically and/or emotionally hurting those Mabel chooses.

Gideon Pines
Unlike her brother, Mabel becomes amused by Gideon, (probably due to his futile attempts to be brave in front of her brother) and even tongue-twists him into a date with her. From then on, Mabel continues keeping in touch with Gideon. However, over time, Mabel starts to become suspicious and views him as a threat to her and Dipper's plans.

William Cipher
The twins have Will Cipher under their control to assist them against his will. However, Will can't escape the hands of the twins because they're much more powerful than him.

in some versions Dipper enjoys torturing him and Mabel feels sorry for him, in other the opposite is true. (often, Bill and Will are related).

Despite her pity, she still tortures him with Dipper, but most of the time, she does care about him, even having a somewhat friendly relationship.

Reverse Soos
Not much is known about Mabel and Soos's relationship but it is speculated that Soos is employed at the Tent of Telepathy, as his counterpart worked at the Mystery Shack. Some have speculated that he (Soos) also works at the Reverse Mystery Shack as a spy for the twins.