Calliope of Homestuck, also known by her chat handle uranianUmbra, is a female cherub Sburb Logo playing a session of the game.
Photo by Yenra
While she initially gave the impression she was a troll this was due to her obsession with their species which extended to cosplaying as one, including giving an alternate version of her name to her "trollsona", Callie Ohpeee. She has lime green bloodSburb Logo, though of a different shade of green than what is shown on the troll hemospectrum.