Alternate Calliope is one of the characters in Homestuck^2: Beyond Canon. In both the Meat and Candy timelines, she has possessed Jade, and in the latter, she has traversed beyond the black hole. As such, both incarnations are present in the Meat universe.
In Meat, Alternate Calliope came into direct intervention of Dirk after he began meddling with the timeline for his own self-gain. While her host is conscious, she easily overpowers his narrative control, but her adamant refusal to insinuate her motives allows Dirk to cleverly circumvent her by physical means. This incarnation of Alternate Calliope is the assumed narrator for the Meat universe (although this may be untrue for those in close proximity to Dirk).
Through Jade, she serves as the guide for those who joined Karkat in pursuit of Dirk, although her motives do not align with theirs perfectly. She has limited communication with the others, presumably not even revealing her identity, for she is referred to by Karkat sarcastically with “MY GOOD FRIEND 'POSSESSED JADE'” and makes no correction.
Instead, Alternate Calliope merely forewarns them of Dirk's growing power with no mention that she knows about his intentions, his activities, or the upcoming cosmic conflict that will ensue upon catching him. It is unknown if she does this because she does not have the ability to, as her host was mute at the end of The Homestuck Epilogues, or because she simply does not wish to disclose such information at this time. Regardless, this behavior contrasts with the Candy Alternate Calliope, whom shared information with Aradia, Sollux, and Davebot.
Alternate Calliope has not yet made an appearance in the Candy universe of Homestuck^2: Beyond Canon.