Troll

An internet troll is someone who willingly harasses other people on the internet. They are often times hackers, breaking into someones profile and defacing it. Homestuck has already introduced four trolls, who seem to have eight more friends. They've been pestering Jade Harley for years now, and have even forced John to change his pesterchum handle. One of them seems to have befriended Rose, who may even be giving them trolling tips. Two of the three trolls we have seen are very bad at trolling, with adiosToreador becoming so freaked out with Dave's sick fantasies ill beats that he blocks Dave, rather than the other way around. carcinoGeneticist tells John that the trolls will, in the kids' future, inadvertently form a sort of friendship with the kids.

The trolls have names tied to the Greek Zodiac. Adding their abbreviated chumhandles to GG, GT, TG, and TT makes the 16 possible two-letter names from the letters A, C, G, and T, the four nucleotides of DNA. grimAuxiliatrix has said that they are from the kids' future, and have access to multiple points from the trolls' past. This has proven to be a confusing and ill thought out plan on their part. Discussions between John and carcinoGeneticist indicate that the trolls find their temporal displacement tiring, as they often have to explain things several times. What the trolls are attempting to do (or stop the kids from doing) is as of yet unclear. It seems likely that the Trolls are players of Sburb, seeing as a strange-looking boy (likely carcinoGeneticist, as he is wearing a shirt with the Cancer sign on it) has with him what appears to be a Kernelsprite, and appears in a similar screen as the Homestuck Kids do in the Underground Base.

GallowsCalibrator mentions to Rose that all 12 trolls are (or possibly have been and finished) playing Sburb together in a single "session", separate from the kids' session. This would mean that the trolls are likely to have no influence whatsoever on the kids' medium or world beyond PesterChum.

Each troll is similar in appearance to one another. They all (so far) resemble human children in body shape. They also all have yellow sunken eyes, pointed teeth and black hair. Each one wears a shirt depicting his or her associated zodiac sign. Their most noticeable features are the colored horns sprouting from their heads. Each troll’s horns appear to reflect that trolls’ zodiac sign, for example GC’s (♎) horns are pointed to a tip and nearly horizontal, while CG’s (♋) are curved and rounded.

List of known trolls

 * apocalypseArisen (Aries)
 * arsenicCatnip (Leo)
 * arachnidsGrip (Scorpio)
 * adiosToreador (Taurus)
 * caligulasAquarium (Aquarius)
 * cuttlefishCuller (Pisces)
 * carcinoGeneticist (Cancer)
 * centaursTesticle (Sagittarius)
 * grimAuxiliatrix (Virgo)
 * gallowsCalibrator (Libra)
 * twinArmageddons (Gemini)
 * terminallyCapricious (Capricorn)

Speculation
It's possible that the trolls are somehow connected to the kids as counterparts or 'evil twins.' A few of them exhibit traits that are the reverse of traits the kids have (i.e. adiosToreador, a possible counterpart to Dave, is very weak-willed and under-confident). Others have 'corrupted' versions of traits the kids have. For example, gallowsCalibrator, who looks a lot like Jade, takes Jade's silliness to a manic level and has a beast-like sense of smell.

Random speculations can draw them to be even connected to the future group, being that if four more protagonists are added then most likely they will have counterparts, which will bring the total to sixteen if the kids and their future counterparts are trolled.

Unencountered Trolls
Several of the trolls not yet seen on screen have been described by the active trolls. GC refers to these other trolls as not "that enthusaistic about trolling" the cast. It is possible that these characters will remain off screen and off Pesterchum for as long as possible so that Andrew can save himself the trouble of drawing them and coming up with individual new ways to abuse the English language. The traits of these semi-known trolls are listed below.
 * A female troll that is "in charge of the timeline management".