Sue Bentley is a fan-created character by Roentgen and one of the major characters in The Hallowed Halls of Fielding. She is a freshman student at Fielding along with Quinn Morgendorffer, and they are each members of the group of upper-class popular girls known as the Tops. She makes her first appearance in the second part of the story as a fellow student in one of Daria Morgendorffer's math classes.
She's ended up as one of the most loathed antagonists in Daria fanfiction!
(Some of what follows might be unreliable, given that the story below was narrated by Sue Bentley herself.)
Sue Bentley was born Susan Bentley to Henry Sandhurst (Tripp) Bentley III, the black sheep of the Bentley family and to Christina Bella de Marchio, an Italian model. Her father died in a bizarre incident in Switzerland before Sue was born and her mother died of a drug overdose when she was two. The Bentleys and the de Marchios fought over Sue's custody, and the Bentleys won custody when Sue was four.
After the Bentleys regained custody of Sue, she was raised under a trust put together by the Bentley family with Tripp's future share of the estate. According to Sue, she has received only minor acknowledgment from the rest of the Bentleys that she's even a member of the family; she has been raised separately from them and they do not visit her. Sue's sole contact with the rest of her family is the administrator of her trust. When Sue reaches twenty-one, she is scheduled to receive the entirety of the trust and the trust will be closed. Sue was shipped off to Fielding at the start of third grade, along with the majority of the other boarding students at Fielding.
Sue claims that one of her grandparents was a supporter of Mussolini. As a result, she defends Il Duce as a great man who tried to save Italy — any suggestion he was a vicious tyrant is, to her mind, a deliberate insult against her family (and thus her). This quirk was the final straw for Tom Sloane.
Sue is a very attractive, blond haired young girl — Sandi Griffin accused her of being a "bottle blond", which Sue denied — and has been voted by the Fielding male student body into the Tops, an exclusive social club of Fielding girls. The only way to get into the Tops is by being voted in by the males, and in general Tops must be a combination of pretty, popular, and well-connected.
There are notable exceptions to this rule. Quinn was voted into the Tops shortly after her arrival at Fielding, which has caused Sue no end of distress. Sue protested that Quinn did not have the social background to be a Top, but it was revealed that the Barksdales were members of the Social Register and that Quinn had the correct pedigree to be a Top.
The other exception is the popularity exception — Sue is generally a conniving and mean-spirited girl who will seemingly do anything to get what she wants. (She might be only popular among boys.) Her actions range from passive-aggressive ("accidentally" spilling a drink on a new blouse bought by Quinn) to shameless lying and pleading for sympathy to throwing her status (or status of affiliates) around to browbeat 'inferiors. She has also shown surprisingly sudden flashes of violence: threatening both student Claire Davidson and later Daria Morgendorffer, throwing screaming fits, and at one point physically attacking Sandi.
Life at Fielding
In addition to her role in Tops, Sue Bentley is also a member of young men and women who are unofficial Drama majors at Fielding. (Fielding has no official majors.) She was in Daria's trigonometry class in Daria's sophomore Fall Term, indicating that Sue might have some skill at mathematics.
During Quinn's freshman year, departing Tops Chair Edmonda "Eddie" Sterling entrusted the care of Tops to both Sue and Quinn Morgendorffer as it appears to be an unofficial rule that Tops Chairs must be seniors and the current junior candidates are considered to be poor leadership material.
Despite her vicious actions, Sue has had two of the most eligible young men at Fielding as boyfriends. Patrick Hackney VII was her boyfriend before Daria and Quinn arrived, but Pat Seven broke up with her in Part 4 after he fell in love with Quinn. Sue then dated Tom Sloane, using emotional manipulation to keep him as her boyfriend and running a constant campaign to mould him into a more 'proper' boyfriend. It appears that Sue cares more for the social status of her boyfriends than anything else. When Tom finally broke ties with her, she responded with a smear campaign, telling the school how he was an abusive and pushy boyfriend (until Angier Sloane quietly threatened legal action).
She took a day off from Fielding, along with Tops' nominal leader Buttons Gwinnett, to comfort Quinn during a bereavement, though she seemed to only be there for appearance's sake and tried to turn the conversation towards her.
In other fanfics
Sue Bentley was the sneering leader of the Axis, a wrestling stable of fanfic villains, in The Excellent S's "Lawndale Fighting Championship". Fans mocked her with signs reading "Mini Mu-Sue-Lini". As Roentgen took "Hallowed Halls" off the internet for two years, Excellent S edited his story to have a "Masked Leader" in place of Sue - while "Hallowed" is back online, LFC has not been reverted yet.