Terezi Pyrope

gallowsCalibrator or GC is a Troll that was introduced in Act 4, currently only known by her chumHandle. She has the same horns and pointy teeth as carcinoGeneticist, but with red sunglasses and shoulder length black hair. She is represented by the symbol ♎ in illustrations. She claims that she is blind, which is supported by her sunglasses, cane, as well as corresponding to her associated zodiac theme (Libra is the scales, a symbol of justice, and 'justice is blind'). She frequently references non-visual perception in unusual contexts, such as claiming to 'smell text' (and maybe most sights) and wanting to listen to John bleed; however, given her mocking nature she might just be lying to confuse Rose and be a troll. In fact, she herself calls Rose "gullible" when she seems to believe, specifically, her claim that she can smell text. Even though she claims to be blind, GC begins trolling Rose by commenting on Mom's martini which is on the pier which means she either must be able to see Rose or is getting information about what she is doing from elsewhere. It is possible that she has synesthesia, due to her association of colors with smells.

GC contacts Rose Lalonde after she enters The Medium and, rather than trolling her (though she claims to be 'hatefriends' with Rose), offers constructive information about the titles of each Sburb player and the voice of the Exile that Rose hears. She mentions the fact that Earth is doomed no matter what, and that the Exiles are the ones who are going to bring back civilization to Earth. GC also knows about Agents but refuses to tell Rose about them, saying it would be more constructive to talk in the future. In GC's reality, she speaks with Rose again in a mere few seconds time.

GC's interactions with John haven't been as constructive, as all she does is laugh, insult him, and threaten to kill him if they should ever meet, prompting John to consider changing his chumhandle. After his arrival in the Land of Wind and Shade, John was tricked by GC into taking a shortcut directly to the seventh gate causing his death (in one timeline) at the hands of the Slumbering One - this in turn caused the death of Jade Harley in this timeline, as John was unable to transport her into the Medium in time to save her home from the asteroid bearing down on it. Rather conflictingly, GC seems to have since shown remorse for her actions and claimed she felt awful for 'killing' him; even helping him through the second gate into the Land of Light and Rain to earn his trust. Whether this is yet another trolling attempt remains to be seen.

Like the other trolls, GC claims to be able to speak to the kids at any point in time that they wish, but rather than work from the end of the kids' adventure as CG and the others do, GC stays linear because weird time stuff gives her a headache. Her overall tone of speech is reminiscent of Jade's speaking patterns.

If GC is to be believed, she has a very strong sense of smell. She even claims to be able to smell text and colors, which is how she's able to use a computer and, to a lesser extent, draw.

Her chumhandle suggests she has an interest in deaths, or more importantly, controlling them (this was confirmed by her semi-successful attempt to kill John). It is also a clever play on her Zodiac symbol, since Libra means justice, she may be the one who controls justice through the gallows. It may be that she enjoys controlling people, as seen in her conversation with John when he was in the Land of Wind and Shade, and she especially enjoys controlling their deaths.