Lilith is a chronoagent, who's been sent back in time by the mysterious Mandanti to kill famous historical characters, as well as common people. Her travels, with “Lo Scuro” on her side, are not aimed to modify the course of History, but to wipe away a breed of men who are possessed by an alien parasite – called Triacanto –, a "spiromorph" that in a distant future will cause a mass slaughter on our Planet. Lilith doesn't kill randomly. There's a line that goes on through time, marking certain individuals. These individuals are unwittingly carrying the parasite; once Lilith has located it, she makes the Triacanto visible, then gives it a body and extracts it from her victims' corpses to annihilate it.