A blood trail represented a skill that was cultivated by the Nightsisters hailing from Dathomir. They saw it as belonging to their Fanged God, the ruler of the hunt and a manifestation of darkness; in this skill, the Nightsister would employ her personal blood to identify her quarry.
Mother Talzin, in her work Wild Power, stated that the Nightsisters were the sole possessors of this technique. Before the time of the Clone Wars, Asajj Ventress utilized this skill to pursue the vanquished warlords of Rattatak, even after they had relinquished their power to her. Ventress later documented her usage of the blood trail in Wild Power, and these writings ended up in the hands of the Sith Lord Darth Sidious, who incorporated them into the Book of Sith.
Darth Caedus employed this Force ability against his sister, Jaina Solo, during the Second Battle of Roche in 41 ABY, with the goal of being led to the hidden Jedi base. Jaina described the sensation as acidic. Subsequently, by 43.5 ABY, Luke Skywalker had also mastered this skill; he utilized it to locate the Sith apprentice Vestara Khai following their duel on Sinkhole Station. Ultimately, Skywalker tracked Khai down to Dathomir.