- Animated Actors: Part of the reason they're medium aware.
- Caustic Critic: Even Italy snarks the fics they have to riff.
- Four-Philosophy Ensemble:
- Twilight is The Cynic
- John is The Apathetic
- Italy is The Optimist
- Harry is The Realist
- Medium Awareness: All of them are medium aware.
The Princess of Friendship in Equestria and the leader of the Riffers.
- Adorkable: When she meets Harry Potter.
- Berserk Button:
- Do NOT remind her that pony porn exists.
- Spelling errors also annoy her.
- Deadpan Snarker: True to canon, she's one of the biggest of the group.
- Fangirl: Of Harry Potter. She claims to have read all seven Harry Potter books a total of 407 times.
- Only Sane Woman: Of the group, though she passes this off to Harry later.
- The Smart Girl: She's the brains of the operation.
- The Smurfette Principle: Played with, as she's the only girl in the group, but also the leader.
- Winged Unicorn: An alicorn princess, of course.
A God of Breath who is part of the group.
- Adorkable: It's John, so that's to be expected.
- Berserk Button: Porn of himself and his friends, and Out of Character depictions of his friends.
- Blow You Away: As the Heir of Breath, he can do this.
- Nice Guy: But he can be pushed to his limits.
- Platonic Life-Partners: With Vriska.
- Shower of Angst: Does this a few times during the riff of Homestuck High.
The personification of the country of Italy.
- Everything's Better with Rainbows: Mocked—he vomits rainbows.
- Keet: He gets along well with Pinkie Pie.
- Nice Guy: Doesn't stop him from snarking the fanfics, though.
- Official Couple: It's mentioned briefly that Germany is his boyfriend.
- Supreme Chef: He likes to make pasta for his pals to calm their nerves.
- Trouser Space: Mentions that he can do this.
- Yaoi Fanboy: He freely admits to being this and says he's never heard of heterosexual Crack Pairings.
The Boy Who Lived and a famous wizard who joined the group in the third episode.
- Deadpan Snarker: John considers him a natural at riffing.
- Nice Guy: Startlingly tolerant of Twilight's fangirling.
- Only Sane Man: Replaces Twilight as such shortly after his arrival.
- Team Dad: To the Riffers.
CJ Croen (the Author)
Not technically a riffer himself, but instead the one who brought the riffers together to do it.
- Author Avatar: And he takes full advantage of it too.
- Reality Warper: Within the story's universe, due to being the author.
- Take That Me: Subverted. Lovino calls fanfiction and people who write fanfiction stupid...and CJ promptly storms out in a huff.
John's sister and the Witch of Space. Guest starred in Homestuck High.
Alfred F. "America" Jones
Embodiment of America and a friend of Italy's. Appears a few times in Homestuck High, as well as in a flashback in Harry Potter Turns to the Lord.
- The Cameo: In "Homestuck High" and "Harry Potter Turns to the Lord".
- Ship Tease: The flashback mentioned above involves him singing about England.
- Trademark Favorite Food: Burgers, the mention of which are what prompts his cameos.
A pony who is best friends with Twilight. Appears in "Cupcakes".
- Genki Girl: As always.
- The Pollyanna: She refuses to let the darkness of Cupcakes to get her down and does her best to cheer everyone up.
Lovino "South Italy" Vargas
Italy's brother. Guest starred in "Romano x Depressed!Reader".
- Berserk Button: He doesn't like how much fanfic writers "defame Spain's character" in shipping fics.
- Hair-Trigger Temper: Which helps a lot with his status as a guest Riffer.
- Ship Tease: With Prussia of all people.
A friend of John's who appears in "My Immortal".
Another friend of John's who appears in "My Immortal".
Another friend of Twilight's who appears in "Pattycakes".
- Card-Carrying Villain: Even Russia mentions an interest in world domination.
- Color-Coded Characters: Umbridge wears pink, Chrysalis wears green, the Condesce wears red and Russia wears white.
- Humiliation Conga: The author puts them through this in order to convince them to let him go.
- Lighter and Softer: Given the comedic tone of the series, they're all a smidge more on the incompetent side than in canon.
One of Harry Potter's arch enemies.
- Big Bad: The leader of the main villains and the one who sends requested badfics.
- Expy: Of Pearl Forrester.
- Faux Affably Evil: Subverted, as any affability has been lost after being in Azkaban for so long.
- Hopeless with Tech: As a witch, Umbridge isn't great with muggle technology.
- Sanity Slippage: Her time in Azkaban apparently messed up her head.
- Smug Snake
An enemy of Twilight Sparkle's, the evil shapeshifting (former) queen of the Changelings.
- Baleful Polymorph: Irony of ironies, the author transforms her into a horsefly during the Humiliation Conga.
- Voluntary Shapeshifter: A power she still has.
Her Imperious Condescension/Betty Crocker
John's arch enemy, an evil troll who ruled Alternia with an iron fist.
- Deadpan Snarker
- The Evil Genius
- Prongs of Poseidon: Her trident, which was briefly turned into a giant salami by the author.
Ivan "Russia" Bravinsky
The embodiment of Russia, friends with Italy. Mostly just joined the villains for fun.
- Affably Evil: A Nice Guy who just happens to want world domination.
- Defeat by Modesty: The author defeats him during the above mentioned Humiliation Conga by making all his clothes disappear, rendering him too embarrassed to do anything until he gets them back.
- Friendly Enemy: To Italy.
- Token Good Teammate: Compared to the other villains.
- The One Guy: The only male among the villains.