* RonTheDeathEater is when a character is either {{Flanderized}} into a JerkAss or more into more of a JerkAss than they were in canon.
* ''Fanfic/WithStringsAttached'' has a lot of these: Terdan, As'taris (almost all Baravadans, actually), the Hunter [[spoiler:(though he undergoes {{Character Development}})]], and most especially Jeft. Also, the Dalns gods are {{Jerkass Gods}}, though this is only talked about, not depicted.
* ''TheHarmonVerse'' has a couple of these: The titular protagonist, Jack Harmon, being the biggest offender of them all.
* ''Fanfic/CalvinAndHobbesTheSeries'': Although Calvin TookALevelInKindness, he still fits this trope.
** [[BunglingInventor Sherman]] even more so.
* In FanFic/TheTaintedGrimoire, everyone in Acidwire is this.
* In the KatawaShoujo fic Lilly Epilogue: Family Matters, Lilly's father is this, even apart from the canonical ParentalAbandonment inflicted on Lilly and Akira for six years. He is incredibly condescending to Hisao and Hanako, referring to them [[HeyYou impersonally]] and making fun of their disabilities. In Hanako's case, he mocks her timidity and asks if she got her burn scars from catching the oven on fire; considering he was warned in advance and the real reason she got them, this is a borderline MoralEventHorizon. [[spoiler:He does apologize to Lilly and accept Hisao in the end, though]].
* Ronan in Fanfic/NarutoVeanganceRevelaitons, in so many ways. He's typically quite arrogant, even towards those he doesn't hold in contempt, and frequently insults his girlfriends and other friends. He also enjoys DisproportionateRetribution, and will kill people who try to stop him from stealing things. The author tried to make Edfred this, but it failed; he's [[EnsembleDarkhorse quite popular]] for standing up to Ronan.
* In ''Fanfic/ProjectIgnition''... Adler- a selfish, arrogant... well, {{Jerkass}}. He'd be an outright villain [[MoralityPet if it weren't for]] [[ChildhoodFriendRomance his childhood friend, Selene]] (well, that and it's kind of hard to be a human villain when there's BETA around).
* Lung from the JackieChanAdventures fic ''Fanfic/QueenOfAllOni'', comes across as this, crossing the MoralEventHorizon in his first real appearance by [[spoiler: kidnapping Jade and nearly KILLING her with ColdBloodedTorture in an attempt to break her to his will!]] (In fact, his backstory reveals that when he was a child, he hid rocks and sticks around the neighborhood to beat the other kids up with). [[spoiler: One reviewer even PRAISED him being KilledOffForReal by Right]].