Of the nine standard Guild poisons, yellow savaughn was his favorite. Inert until mixed with alcohol, it was relatively safe to refine and carry on one's person. The toxin built up in the kidneys over the course of hours after ingestion, giving ample time to gain distance from the victim before its effects became apparent. Even then it had no telltales to indicate that anything more than overindulgence played a role in the death – no blackened fingertips, no bloodied eyes, no spasms, just sleepiness that led to suffocation while asleep. To be sure a trained surgeon would recognize the swollen kidneys of yellow savaughn poisoning, but by then the matter would be well out of their hands.
Unless, of course, the victim was one of the unfortunate few with a congenital allergy to savaughn root. Then it would be only moments before his or her tongue would swell up and block the airway, gums bleeding profusely until the victim choked to death. All while the assassin was no doubt nearby, perhaps stripping off a cook's apron and sprinting through the kitchen toward a convenient alley window.
It was under circumstances similar to this that Farningwold found himself crouching in a pile of rotting cabbage leaves, having leapt from the warm but suddenly inhospitable kitchen into one of the colder and danker of Sliorek's many blind alleys. He took time to sloppily douse three throwing blades with black gall-resin thinned with turpentine -- his least-favorite decoction – before sprinting off toward the street. He had just reached the mouth of the alley when the back gate of the victim's house slammed open as the house guard gave chase. He let one blade fly and ran east, toward the Knot.
He wondered how he'd be able to collect the second half of his payment, since his contact had been sitting across the table from the eight-year-old boy that had been the target. Funny thing, that. As he approached a narrow spot in the street he palmed a second blade and nicked two women who had been chatting over a fruitseller's cart. They fell almost immediately; hopefully the fuss would choke the lane with good Samaritans. He didn’t think they'd die from such a short cut. A left and two right turns later he inverted his coat and shed his false moustache.
He also shed any pretense of maintaining the Guild code of client anonymity. Why would Errick want his best friend and business partner's son dead?