Jerkass/Web Original

Trolls, obviously. Especially types like Gray Jaeger on deviantart who is also like this on Tanuke.com, also Rents of Slapstick Anarchy and Habermann of Metokur.org both count, as well as most if not all editors on ED.
In the League of Intergalactic Cosmic Champions Kiehart & Cyber-9 qualify.
Dr. Horrible's Sing-Along Blog gives us Captain Hammer.
Cortez and Player from The Leet World, although Cortez mellows a bit over the course of the first season, becoming more of a Jerk with a Heart of Gold.
Master Chief. Enough said, really. Travis from the same series has his moments, but is nowhere near as extreme an example as the Chief. Cameron and Cody as well. Mostly Cody.
Too many characters in Red vs. Blue fit this trope to name at once, most notably Sarge and Church.
Gordon Freeman is depicted having this kind of personality in Freeman's Mind.
James Potter in the fanfic series "Adventures with the Potterz." [1]^{[dead link]}
Yugi from Yu-Gi-Oh the Abridged Series. Joey saying "Yugi is such an asshole!" is practically a Catch Phrase.
Quite a few characters in Survival of the Fittest at times. One of the most notable was Monty Pondsworth of v4 pre-game, who is a schoolyard bully with mommy issues. Many characters don't like him for a reason. Whilst Monty never actually made it onto the island, two characters in particular have taken his spot as the top jerkasses in V4. The characters in question being Philip Ward, the resident school bully who whilst not technically a player, has commitied some truly dickish acts including stealing Dominic Stratford's stuff, beating Maria Graham to a pulp, and wearing a Sonic the Headgehog T-Shirt. and Maxwell Lombardi, a smug, egocentrical if somewhat well-dressed English "gentleman". Unlike Philip though, Maxwell quickly wasted no time in crossing the Moral Event Horizon after he kills Augustus MacDougal and realises that Evil Feels Good...
The Irate Gamer, both on his series and in real life.
Jerry's dad and son in Jerry.
Global Guardians PBEM Universe: The Aryan is a Flying Brick crimefighter who also happens to be a white supremacist. He absolutely repudiates violence against non-whites (except, you know, when they are non-white criminals), and saves the lives of non-whites as often as he does whites (he believes that by doing this, he is showing himself and his race to be "good examples), but is nonetheless a racist asshair and is quite vocal about his views on race relations.
Almost all of the good guys in A Very Potter Musical qualify, but Harry takes the cake. He's got an ego the size of the sun, constantly rubs it in the faces of all the other characters, and thinks the fact that he's Harry Potter makes him entitled to everything. By contrast, Voldemort's actually a pretty nice guy. Ron, too, especially since he explicitly says "I know I've been a Jerkass lately" when apologizing to Hermione.
Saturday Morning Breakfast Cereal gives an alternate origin story for Don Quixote in which he was actually a real hero, but also a Jerkass to his biographer Sancho, resulting in the unflattering biography we know today.
Tom from Echo Chamber.

Tom (to Zack): If you get in front of the camera, I will stab you. I will actually stab you!

Encyclopedia Dramatica is all about this. From showing all the spoilers at the top of the Harry Potter page to redirecting you to shock images when you search for "kittens", the wiki is the very embodiment of this trope.
Black Kitty from Goodbye Kitty. He always tries to kill White Kitty out of bitterness of being The Unfavorite (but thankfully, it always backfires).
Stupid Mario Brothers:
- Bob and Joe of RMA Studios.
- Wario and Waluigi in ealier seasons.
- Snake can sometimes be this too but then becomes Jerk with a Heart of Gold.
- Mario himself has even shown this throughout the show, but it shows up most prominently in Season 4.
Spc.Crota has a tendency to make offensive comments.
Every character in the web series Sanity Not Included is a jerkass, but extra points go to Lyle for having the last name McDouchebag to emphasize this.
Cardin Winchester from the early volumes of RWBY.

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