The Poisoner is mainly depicted as a Yuan-Ti Abomination, shown as a large cyan blue scaled cobra. Jakirl can change his form into any of the three forms of Yuan-Ti, switching to each for a different reason. Pureblood to help blend in with normal people, Halfblood and changing throughout all the different Halfblood forms, and Abomination for their strength and power.
Jarkirl is the deadliest assassin to have ever existed. When the Poisoner slinks into the shadows, it turns every section of him darker and barely visible. He is the patron god of all assassins, many assassins pray to the Poisoner before they go off to assassinate a target. He carries a set of daggers that once it hits a target, the deadliest poisons flow into their body and a light crossbow with bolts with vials of a contact poison tied to them that shatter on contact. All that is needed to call forth the Poisoner would be either a vial of poison, a poisoned dagger or arrow, or the fang of a venomous serpent.